Augmented reality local tone mapping for light-transmissive display panel systems and methods

ABSTRACT

Systems and methods are provided for displaying augmented reality image content perceived as being overlaid on background image content viewed through a light-transmissive viewing surface. Image processing circuitry may receive input augmented reality image data corresponding with a pixel position on the display panel, determine a perceived background brightness metric indicative of background brightness level at the pixel position based at least in part on captured background image data and an ambient lighting metric, determine a target tone mapping based at least in part on the perceived background brightness metric, and determine display augmented reality image data to be used by a display panel to display the augmented reality image content least in part by applying the target tone mapping to the input augmented reality image data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalApplication No. 62/898,523, filed Sep. 10, 2019, and entitled,“AUGMENTED REALITY LOCAL TONE MAPPING FOR LIGHT-TRANSMISSIVE DISPLAYPANEL SYSTEMS AND METHODS,” which is incorporated herein by reference inits entirety for all purposes.

SUMMARY

A summary of certain embodiments disclosed herein is set forth below. Itshould be understood that these aspects are presented merely to providethe reader with a brief summary of these certain embodiments and thatthese aspects are not intended to limit the scope of this disclosure.Indeed, this disclosure may encompass a variety of aspects that may notbe set forth below.

The present disclosure generally relates to display panels (e.g.,electronic displays), which may be implemented and/or operated todisplay one or more images (e.g., image frames and/or pictures) topresent visual representations of information. Accordingly, electronicsystems (e.g., devices), such as computers, mobile phones, portablemedia devices, tablets, televisions, virtual-reality headsets, andvehicle dashboards, among many others, often include and/or utilize oneor more display panels. In any case, a display panel may generallydisplay an image by actively controlling light emission from its displaypixels, which each includes one or more color component sub-pixels,based at least in part on image data indicative of target luminance(e.g., brightness level and/or grayscale level) of the display pixels ina corresponding image. For example, based on corresponding image data, adisplay panel may display augmented reality (e.g., virtual) imagecontent overlaid on background (e.g., real) image content, therebyproviding an augmented reality (AR) experience.

To facilitate providing an augmented reality experience, in someinstances, a display panel may be implemented and/or operated toactively display (e.g., reproduce) background image content, forexample, by controlling light emission from its display pixels based atleast in part on corresponding image data generated by an image sensor,such as a camera. In other instances, a display panel may be implemented(e.g., deployed) on a light-transmissive viewing surface, such as a lensof a wearable (e.g., headset) electronic device, a windshield of anautomotive vehicle, and/or the like. In such instances, thelight-transmissive viewing surface may enable environmental light topass therethrough, thereby enabling a user (e.g., wearer, driver, rider,or operator) to visually perceive background image content. Thus, insuch instances, the display panel may facilitate providing an augmentedreality experience by displaying augmented reality image contentanchored to one or more specific locations in background image contentwithout actively displaying (e.g., reproducing) the background imagecontent.

However, at least in some instances, perception of augmented realityimage content may be dependent on optical characteristics, such as colorand/or brightness, of background image content on which the augmentedreality image content is overlaid (e.g., displayed and/or presented).For example, displaying augmented reality image content overlaid onbrighter (e.g., higher luma value) background image content may reduceperceived contrast in the augmented reality image content, therebyresulting in the augmented reality image content appearing washed outcompared to displaying the augmented reality image content overlaid ondarker (e.g., lower luma value) background image content. In otherwords, at least in some instances, optical (e.g., visual)characteristics of background image content may affect perceived qualityof augmented reality image content overlaid thereon and, thus, perceivedquality of an electronic system providing the augmented realityexperience.

Accordingly, to facilitate improving augmented reality experience, thepresent disclosure describes techniques for implementing and/oroperating an electronic system, which includes one or more displaypanels each implemented (e.g., deployed) on a light-transmissive viewingsurface, to adaptively adjust presentation (e.g., display) of augmentedreality image content based at least in part on expected optical (e.g.,visual) characteristics of background image content on which theaugmented reality image content is to be overlaid. To facilitatedetermining the expected optical characteristics of background imagecontent, in some embodiments, the electronic system may include one ormore optical sensors. In particular, the optical sensors may include oneor more ambient light sensors, for example, implemented and/or operatedto determine (e.g., generate and/or output) an ambient lighting metricindicative of an average (e.g., mean) brightness level (e.g., lumavalue) of background (e.g., environmental and/or ambient) light.

Additionally, the optical sensors may include one or more image sensors,such as a camera, implemented and/or operated to capture frames ofbackground image content. To capture a frame of background imagecontent, in some embodiments, an image sensor may determine (e.g., senseand/or measure) optical characteristics, such as color and/or brightnesslevel, at specific locations (e.g., points) in the frame, for example,which each corresponds with a pixel position at which a display pixel isimplemented on a display panel. The image sensor may determine (e.g.,generate and/or output) background image data to indicate the sensedoptical characteristics of the background image content. In someembodiments, the image sensor may capture background image content at aspecific location by determining captured background image data in colorcomponent domains, which may be converted to a luma domain beforesubsequent processing. For example, a red component brightness (e.g.,grayscale) level indicated in the captured background image data, a bluecomponent grayscale level indicated in the captured background imagedata, and a green component grayscale level indicated in the capturedbackground image data may be weighted (e.g., using coefficients) andcombined (e.g., summed together) to determine a luma value indicative ofachromatic brightness level at the specific location in the backgroundimage content.

To facilitate adaptively adjusting presentation of augmented realityimage content, in some embodiments, the electronic system may includeimage processing circuitry implemented and/or operated to process (e.g.,adjust) augmented reality image data before corresponding augmentedreality image content is displayed. In particular, in some embodiments,the image processing circuitry may receive source augmented realityimage data from an image source, process the source augmented realityimage data to determine augmented reality display image data thataccounts (e.g., compensates) for expected optical characteristics ofbackground image content, and output the augmented reality display imagedata to enable a display panel to present (e.g., display) correspondingaugmented reality image content using the augmented reality display(e.g., processed and/or compensated) image data, for example, instead ofusing the source augmented reality image data. To facilitate accountingfor expected optical characteristics of background image content, insome embodiments, the image processing circuitry may include abackground analysis block (e.g., circuitry group) and a tone mappingblock (e.g., circuitry group).

In particular, in some embodiments, a background analysis block in theimage processing circuitry may be implemented and/or operated todetermine one or more perceived background brightness metrics, which areeach indicative of a background brightness level expected to beperceived by a user's eye at a specific location in a frame ofbackground image content. Thus, in some embodiments, the backgroundanalysis block may determine a perceived background brightness metricassociated with a specific location in background image content and,thus, a corresponding pixel position on a display panel based at leastin part on corresponding background image data and an ambient lightingmetric, for example, in addition to a tint strength applied on acorresponding light-transmissive viewing surface while the display panelis presenting augmented reality image content and/or a targettransparency (e.g., opacity) of the augmented reality image content.However, in some embodiments, an image sensor (e.g., camera) of anelectronic system that captures background image data may be spatiallyoffset from a user's eye and, thus, captured background image contentmay differ from the background image content that will actually beperceived by the user's eye via a light-transmissive viewing surface ofthe electronic system. Accordingly, to facilitate determining aperceived background brightness metric, in some embodiments, the imageprocessing circuitry may process captured background image data tore-project corresponding background image content from the perspectiveof the image sensor to the expected perspective of the user's eye.

In some embodiments, a tone mapping block in the image processingcircuitry may process input (e.g., source) augmented reality image databy tone mapping the input augmented reality image data based at least inpart on an associated set of operational parameters, which includes aperceived background brightness metric associated with background imagecontent on which corresponding augmented reality image content is to beoverlaid, for example, in addition to target transparency of theaugmented reality image content and/or a histogram of brightness levels(e.g., luma values) in preceding (e.g., directly previous frame)augmented reality image content. To facilitate improving perceivedquality of augmented reality image content, in some embodiments, thetone mapping block may apply different tone mappings under differentsets of operational parameters. For example, the tone mapping block mayapply a stronger tone mapping to input augmented reality image data toboost contrast of corresponding augmented reality when the augmentedreality image content is to be displayed on brighter background imagecontent compared to when the augmented reality image content is to bedisplayed on darker background image content. In other words, in someembodiments, the tone mapping block may apply a stronger tone mapping toinput augmented reality image content associated with a set ofoperational parameters including a higher (e.g., larger and/or brighter)perceived background brightness metric compared to the tone mappingapplied to input augmented reality image content associated with a setof operational parameters including a lower (e.g., smaller and/ordarker) perceived background brightness metric.

As another example, the tone mapping block may additionally oralternatively apply a stronger tone mapping to input augmented realityimage data to boost contrast of corresponding augmented reality whendirectly preceding augmented reality image content is darker whileapplying a weaker tone mapping to the input augmented reality image datawhen the directly preceding augmented reality image content is brighter.In other words, in some embodiments, the tone mapping block mayadditionally or alternatively apply a stronger tone mapping to inputaugmented reality image data associated with a set of operationalparameters including a previous augmented reality content histogram thatis skewed brighter and a weaker tone mapping to input augmented realityimage data associated with a set of operational parameters including aprevious augmented reality content histogram that is skewed darker. As afurther example, the tone mapping block may additionally oralternatively apply a stronger tone mapping to input augmented realityimage data associated with a set of operational parameters indicative ofa lower target transparency while applying a weaker tone mapping toinput augmented reality image data associated with a set of operationalparameters indicative of a higher target transparency.

To facilitate tone mapping, in some embodiments, the tone mapping blockmay include and/or utilize one or more tone map look-up-tables (LUTs).In particular, a tone map look-up-table may be implemented to map acolor component (e.g., red, green, or blue) brightness (e.g., grayscale)level indicated in augmented reality input image data to a correspondingcolor component brightness level indicated in output (e.g., display)augmented reality image data, for example, which is supplied todownstream image processing circuitry for further processing and/or adisplay panel to enable the display panel to display correspondingaugmented reality image content.

To facilitate adaptively adjusting tone mapping applied to augmentedreality image content, in some embodiments, the tone mapping block mayinclude and/or utilize (e.g., consider) multiple different candidatetone map look-up-tables, for example, each corresponding with adifferent set of operational parameters. In particular, to facilitatetone mapping input augmented reality image data, in such embodiments,the tone mapping block may determine (e.g., receive) a set ofoperational parameters associated with the input augmented reality imagedata and, thus, corresponding augmented reality image content.Additionally, the tone mapping block may select a candidate tone maplook-up-table corresponding with the set of operational parametersassociated with the augmented reality image content as a target tone maplook-up-table and apply the target tone map look-up-table to the inputaugmented reality image data to determine corresponding output augmentedreality image data.

However, at least in some instances, perceived brightness of backgroundimage content may vary over an image frame. In fact, at least in someinstances, capturing different portions of background image content,which are or would be perceived by a user as having approximately (e.g.,substantially) the same optical characteristics, may nevertheless resultin captured background image data indicating different backgroundbrightness levels and, thus, different perceived background brightnessmetrics being determined, for example, due to the background imagecontent including real world and/or natural content. In other words, atleast in some instances, determining perceived background brightnessmetrics directly using captured background image data or evenre-projected background image data may result in each pixel positionbeing associated with a different set of operational parameters and,thus, different tone mappings (e.g., target tone map look-up-tables)being applied.

To facilitate improving operational and/or computational efficiency, insome embodiments, an electronic system (e.g., image processing circuitryand/or background analysis block) may determine a local tone map grid,which includes one or more grid zones (e.g., regions). As will bedescribed in more detail below, a grid zone in a local tone map gridcorresponding with an image frame may group together adjacent pixelpositions in an active region of a display panel that will be used todisplay augmented reality image content overlaid on background imagecontent having approximately (e.g., substantially) the same opticalcharacteristics. To facilitate identifying background image content withapproximately the same optical characteristics, in some embodiments, theelectronic system may filter re-projected background image data. Forexample, image processing circuitry implemented in the electronic systemmay low pass filter the re-projected background image data to determinefiltered background image data, which, at least in some instances, mayreduce the number of different background brightness level compared tothe re-projected background image data.

In other words, compared to corresponding re-projected background imagedata, filtered background image data corresponding with a frame ofbackground image content may increase likelihood that adjacent pixelpositions, which are associated with approximately the same backgroundoptical characteristics, are identified as having the same backgroundbrightness level (e.g., luma value). Merely as an illustrativenon-limiting example, first re-projected background image dataassociated with a first pixel position may indicate a first brightnesslevel of sixty-five whereas second re-projected background image dataassociated with a second (e.g., different) pixel position, which isadjacent the first pixel position, may indicate a second brightnesslevel of sixty-six. However, low pass filtering the first re-projectedbackground image data and the second re-projected background image datamay result in first filtered background image data corresponding withthe first pixel position and second filtered background image datacorresponding with the second pixel position indicating the samefiltered background brightness level (e.g., luma value). In other words,at least in some instances, filtering re-projected background image datamay result in captured background brightness levels being rounded to acoarser granularity, which, at least in some instances, may facilitatereducing the number of different operational parameter sets associatedwith the active area and, thus, the number of different tone mapping tobe applied in a frame of augmented reality image content.

As such, in some embodiments, an electronic system (e.g., imageprocessing circuitry and/or background analysis block) may determine alocal tone map grid for a frame based at least in part on analysis offiltered background image data corresponding with background imagecontent over which an active region of a display panel is expected todisplay augmented reality image content. In particular, the electronicsystem may analyze the filtered background image data to identify one ormore grid zones in the active region that each groups together adjacentpixel positions associated with the same filtered background brightnesslevel. To help illustrate, continuing with the above example, theelectronic system may include the first pixel position and the secondpixel position, which is adjacent the first pixel position, in the samegrid zone of the local tone map grid due to a first filtered backgroundbrightness level indicated in the first filtered background image datamatching a second filtered background brightness level indicated in thesecond background filtered image data.

In other words, since an ambient lighting metric is indicative ofaverage background brightness level, pixel positions in the same gridzone may be associated with the same perceived background brightnessmetric. In fact, in some embodiments, each pixel position in a grid zonemay be associated with the same set of operational parameters. In otherwords, in some such embodiments, a tone mapping block may apply the sametone mapping (e.g., target tone map look-up-table) to input augmentedreality image data corresponding with each pixel position in a gridzone, for example, while applying a different tone mapping to inputaugmented reality image data corresponding with a pixel position in adifferent grid zone.

As such, to facilitate appropriately tone mapping input augmentedreality image data, in some embodiments, the tone mapping block maydetermine (e.g., identify) a grid zone that includes a correspondingpixel position. In some embodiments, a frame of augmented reality imagedata may be written to display pixels and, thus, processed in rasterorder. Accordingly, in such embodiments, the electronic system (e.g.,image processing circuitry and/or tone mapping block) may determine apixel position corresponding with augmented reality image data based atleast in part on its processing order relative to other augmentedreality image data in the same frame, for example, in view of pixeldimensions of a display panel and/or an active region of the displaypanel that will be used to display the frame of augmented reality imagecontent.

Based at least in part on the grid zone including a pixel positioncorresponding with input augmented reality image data, the tone mappingblock may determine (e.g., identify and/or select) a target tone mapping(e.g., tone map look-up-table) associated with the grid zone and/or aset of operational parameters corresponding with the grid zone. Asdescribed above, the tone mapping block may apply the target tonemapping to input color component brightness levels indicated in theinput augmented reality image data to determine corresponding outputcolor component brightness levels to be indicated in output (e.g.,display, processed, and/or tone mapped) augmented reality image data. Inthis manner, as will be described in more detail below, the techniquesdescribed in the present disclosure may facilitate adaptively (e.g.,spatially) varying tone mapping applied in a frame of augmented realityimage content and/or adaptively (e.g., temporally) varying tone mappingapplied in different frames of augmented reality image content based atleast in part on optical characteristics (e.g., brightness level) ofbackground image content, which, at least in some instances, mayfacilitate improving perceived quality of augmented reality imagecontent presented on a display panel of an electronic system and, thus,an augmented reality experience provided by the electronic system.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the present disclosure may be better understood uponreading the following detailed description and upon reference to thedrawings in which:

FIG. 1 is a block diagram of an electronic system including one or moredisplay panels, in accordance with an embodiment of the presentdisclosure;

FIG. 2 is an example of the electronic device of FIG. 1 includingdisplay panels implemented on light-transmissive viewing surfaces, inaccordance with an embodiment of the present disclosure;

FIG. 3 is an example of image frames perceived through thelight-transmissive viewing surfaces of FIG. 2 , in accordance with anembodiment of the present disclosure;

FIG. 4 is another example of a display panel implemented on alight-transmissive viewing surface, in accordance with an embodiment ofthe present disclosure;

FIG. 5 is a block diagram of an example portion of the electronic systemof FIG. 1 including image processing circuitry, which includes a localtone mapping block and a background analysis block, and a display panel,in accordance with an embodiment of the present disclosure;

FIG. 6 is an example of a frame of captured background image content, inaccordance with an embodiment of the present disclosure;

FIG. 7 is an example of a frame of re-projected background image contentdetermined by re-projecting the captured background image content ofFIG. 6 , in accordance with an embodiment of the present disclosure;

FIG. 8 is an example of a frame of filtered background image contentdetermined by filtering the re-projected background image content ofFIG. 7 , in accordance with an embodiment of the present disclosure;

FIG. 9 is an example of a local tone map grid overlaid on the filteredbackground image content of FIG. 8 , in accordance with an embodiment ofthe present disclosure;

FIG. 10 is a block diagram of an example of the local tone mapping blockof FIG. 5 , in accordance with an embodiment of the present disclosure;

FIG. 11 is a flow diagram of an example process for operating the imageprocessing circuitry of FIG. 5 , in accordance with an embodiment of thepresent disclosure;

FIG. 12 is a flow diagram of an example process for analyzing abackground on which augmented reality image content is expected to beoverlaid to determine a perceived background brightness metric, inaccordance with an embodiment of the present disclosure;

FIG. 13 is a flow diagram of an example process for analyzing abackground on which augmented reality image content is expected to beoverlaid to determine a local tone map grid, in accordance with anembodiment of the present disclosure; and

FIG. 14 is an example of a process for determining a target local tonemapping to be applied to augmented reality image data corresponding withaugmented reality image content, in accordance with an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will bedescribed below. These described embodiments are only examples of thepresently disclosed techniques. Additionally, in an effort to provide aconcise description of these embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but may nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the presentdisclosure, the articles “a,” “an,” and “the” are intended to mean thatthere are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.Additionally, it should be understood that references to “oneembodiment” or “an embodiment” of the present disclosure are notintended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features.

The present disclosure generally relates to display panels (e.g.,electronic displays), which may be implemented and/or operated todisplay one or more images (e.g., image frames and/or pictures) topresent visual representations of information. Accordingly, electronicsystems (e.g., devices), such as computers, mobile phones, portablemedia devices, tablets, televisions, virtual-reality headsets, andvehicle dashboards, among many others, often include and/or utilize oneor more display panels. In any case, a display panel may generallydisplay an image by actively controlling light emission from its displaypixels, which each includes one or more color component sub-pixels,based at least in part on image data indicative of target luminance(e.g., brightness level and/or grayscale level) of the display pixels ina corresponding image. For example, based on corresponding image data, adisplay panel may display augmented reality (e.g., virtual) imagecontent overlaid on background (e.g., real) image content, therebyproviding an augmented reality (AR) experience.

To facilitate providing an augmented reality experience, in someinstances, a display panel may be implemented and/or operated toactively display (e.g., reproduce) background image content, forexample, by controlling light emission from its display pixels based atleast in part on corresponding image data generated by an image sensor,such as a camera. In other instances, a display panel may be implemented(e.g., deployed) on a light-transmissive viewing surface, such as a lensof a wearable (e.g., headset) electronic device, a windshield of anautomotive vehicle, and/or the like. In particular, thelight-transmissive viewing surface may enable environmental light topass therethrough, thereby enabling a user (e.g., wearer, driver, rider,or operator) to visually perceive background image content. Thus, insuch instances, the display panel may facilitate providing an augmentedreality experience by displaying augmented reality image contentanchored to one or more specific locations in background image contentwithout actively displaying (e.g., reproducing) the background imagecontent.

However, at least in some instances, perception of augmented realityimage content may be dependent on optical characteristics, such as colorand/or brightness, of background image content on which the augmentedreality image content is overlaid (e.g., displayed and/or presented).For example, displaying augmented reality image content overlaid onbrighter (e.g., higher luma value) background image content may reduceperceived contrast in the augmented reality image content, therebyresulting in the augmented reality image content appearing washed outcompared to displaying the augmented reality image content overlaid ondarker (e.g., lower luma value) background image content. In otherwords, at least in some instances, optical (e.g., visual)characteristics of background image content may affect perceived qualityof augmented reality image content overlaid thereon and, thus, perceivedquality of an electronic system providing the augmented realityexperience.

Accordingly, to facilitate improving augmented reality experience, thepresent disclosure describes techniques for implementing and/oroperating an electronic system, which includes one or more displaypanels each implemented (e.g., deployed) on a light-transmissive viewingsurface, to adaptively adjust presentation (e.g., display) of augmentedreality image content based at least in part on expected optical (e.g.,visual) characteristics of background image content on which theaugmented reality image content is to be overlaid. To facilitatedetermining the expected optical characteristics of background imagecontent, in some embodiments, the electronic system may include one ormore optical sensors. In particular, in some embodiments, the opticalsensors may include one or more ambient light sensors, for example,implemented and/or operated to determine (e.g., generate and/or output)an ambient lighting metric indicative of an average (e.g., mean)brightness level (e.g., luma value) of background (e.g., environmentaland/or ambient) light.

Additionally, the optical sensors may include one or more image sensors,such as a camera, implemented and/or operated to capture frames ofbackground image content. To capture a frame of background imagecontent, in some embodiments, an image sensor may determine (e.g., senseand/or measure) optical characteristics, such as color and/or brightnesslevel, at specific locations (e.g., points) in the frame, for example,which each corresponds with a pixel position at which a display pixel isimplemented on a display panel. The image sensor may determine (e.g.,generate and/or output) background image data to indicate the sensedoptical characteristics of the background image content. In someembodiments, the image sensor may capture background image content at aspecific location by determining captured background image data in colorcomponent domains, which may be converted to a luma domain beforesubsequent processing. For example, a red component brightness (e.g.,grayscale) level indicated in the captured background image data, a bluecomponent grayscale level indicated in the captured background imagedata, and a green component grayscale level indicated in the capturedbackground image data may be weighted (e.g., using coefficients) andcombined (e.g., summed together) to determine a luma value indicative ofachromatic brightness level at the specific location in the backgroundimage content.

To facilitate adaptively adjusting presentation of augmented realityimage content, in some embodiments, the electronic system may includeimage processing circuitry implemented and/or operated to process (e.g.,adjust) augmented reality image data before the augmented reality imagedata is used to display corresponding augmented reality image content.In particular, in some embodiments, the image processing circuitry mayreceive source augmented reality image data from an image source,process the source augmented reality image data to determine augmentedreality display image data that accounts (e.g., compensates) forexpected optical characteristics of background image content, andoutputs the augmented reality display image data to enable a displaypanel to present (e.g., display) corresponding augmented reality imagecontent using the augmented reality display (e.g., processed and/orcompensated) image data, for example, instead of the source augmentedreality image data. To facilitate accounting for expected opticalcharacteristics of background image content, in some embodiments, theimage processing circuitry may include a background analysis block(e.g., circuitry group) and a tone mapping block (e.g., circuitrygroup).

In particular, in some embodiments, a background analysis block in theimage processing circuitry may be implemented and/or operated todetermine one or more perceived background brightness metrics, which areeach indicative of a background brightness expected to be perceived by auser's eye at a specific location in a frame of background imagecontent. Thus, in some embodiments, the background analysis block maydetermine a perceived background brightness metric associated with aspecific location in background image content and, thus, a correspondingpixel position on a display panel based at least in part oncorresponding background image data and an ambient lighting metric, forexample, in addition to a tint strength applied on a correspondinglight-transmissive viewing surface while the display panel is presentingaugmented reality image content and/or a target transparency (e.g.,opacity) of the augmented reality image content. However, in someembodiments, an image sensor (e.g., camera) of an electronic system thatcaptures background image data may be spatially offset from a user's eyeand, thus, captured background image content may differ from thebackground image content that will actually be perceived by the user'seye via a light-transmissive viewing surface of the electronic system.Accordingly, to facilitate determining a perceived background brightnessmetric, in some embodiments, the image processing circuitry may processcaptured background image data to re-project corresponding backgroundimage content from the perspective of the image sensor to the expectedperspective of the user's eye.

In some embodiments, a tone mapping block in the image processingcircuitry may process input (e.g., source) augmented reality image databy tone mapping the input augmented reality image data based at least inpart on an associated set of operational parameters, which includes aperceived background brightness metric associated with background imagecontent on which corresponding augmented reality image content is to beoverlaid, for example, in addition to target transparency of theaugmented reality image content and/or a histogram of brightness levels(e.g., luma values) in a preceding (e.g., directly previous) augmentedreality image content. To facilitate improving perceived quality ofaugmented reality image content, in some embodiments, the tone mappingblock may apply different tone mappings under different sets ofoperational parameters. For example, the tone mapping block may apply astronger tone mapping to input augmented reality image data to boostcontrast of corresponding augmented reality when the augmented realityimage content is to be displayed on brighter background image contentcompared to when the augmented reality image content is to be displayedon darker background image content. In other words, in some embodiments,the tone mapping block may apply a stronger tone mapping to inputaugmented reality image content associated with set of operationalparameters including a higher (e.g., larger and/or brighter) perceivedbackground brightness metric compared to the tone mapping applied toinput augmented reality image content associated with set of operationalparameters including a lower (e.g., smaller and/or darker) perceivedbackground brightness metric.

As another example, the tone mapping block may additionally oralternatively apply a stronger tone mapping to input augmented realityimage data to boost contrast of corresponding augmented reality whendirectly preceding augmented reality image content is darker whileapplying a weaker tone mapping to the input augmented reality image datawhen the directly preceding augmented reality image content is brighter.In other words, in some embodiments, the tone mapping block mayadditionally or alternatively apply a stronger tone mapping to inputaugmented reality image data associated with set of operationalparameters including a previous augmented reality content histogram thatis skewed brighter and a weaker tone mapping to input augmented realityimage data associated with set of operational parameters including aprevious augmented reality content histogram that is skewed darker. As afurther example, the tone mapping block may additionally oralternatively apply a stronger tone mapping to input augmented realityimage data associated with a set of operational parameters indicative ofa lower target transparency while applying a weaker tone mapping toinput augmented reality image data associated with a set of operationalparameters indicative of a higher target transparency.

To facilitate tone mapping, in some embodiments, the tone mapping blockmay include and/or utilize one or more tone map look-up-tables (LUTs).In particular, a tone map look-up-table may be implemented to map acolor component (e.g., red, green, or blue) brightness (e.g., grayscale)level indicated in augmented reality input image data to a correspondingcolor component brightness level indicated in output (e.g., display)augmented reality image data, for example, which is supplied todownstream image processing circuitry for further processing and/or adisplay panel to enable the display panel to display correspondingaugmented reality image content.

To facilitate adaptively adjusting tone mapping applied to augmentedreality image content, in some embodiments, the tone mapping block mayinclude and/or utilize (e.g., consider) multiple different candidatetone map look-up-tables, for example, each corresponding with adifferent set of operational parameters. In particular, to facilitatetone mapping input augmented reality image data, in such embodiments,the tone mapping block may determine (e.g., receive) a set ofoperational parameters associated with the input augmented reality imagedata and, thus, corresponding augmented reality image content.Additionally, the tone mapping block may select a candidate tone maplook-up-table corresponding with the set of operational parametersassociated with the augmented reality image content as a target tone maplook-up-table and apply the target tone map look-up-table to the inputaugmented reality image data to determine corresponding output augmentedreality image data.

However, at least in some instances, perceived brightness of backgroundimage content may vary over an image frame. In fact, at least in someinstances, capturing different portions of background image content,which are or would be perceived by a user as having approximately (e.g.,substantially) the same optical characteristics, may nevertheless resultin captured background image data indicating different brightness levelsand, thus, different perceived background brightness metrics beingdetermined, for example, due to the background image content includingreal world and/or natural content. In other words, at least in someinstances, determining perceived background brightness metrics directlyusing captured background image data or even re-projected backgroundimage data may result in each pixel position being associated with adifferent set of operational parameters and, thus, different tonemappings (e.g., target tone map look-up-tables) being applied.

To facilitate improving operational and/or computational efficiency, insome embodiments, an electronic system (e.g., image processing circuitryand/or background analysis block) may determine a local tone map grid,which includes one or more grid zones (e.g., regions). As will bedescribed in more detail below, a grid zone in a local tone map gridcorresponding with an image frame may group together adjacent pixelpositions in an active region of a display panel that will be used todisplay augmented reality image content overlaid on background imagecontent having approximately (e.g., substantially) the same opticalcharacteristics. To facilitate identifying background image content withapproximately the same optical characteristics, in some embodiments, theelectronic system may filter re-projected background image data. Forexample, image processing circuitry implemented in the electronic systemmay low pass filter the re-projected background image data to determinefiltered background image data, which, at least in some instances, mayreduce the number of different background brightness level compared tothe re-projected background image data.

In other words, compared to corresponding re-projected background imagedata, filtered background image data corresponding with a frame ofbackground image content may increase likelihood that adjacent pixelpositions, which are associated with approximately the same backgroundoptical characteristics, are identified as having the same backgroundbrightness level (e.g., luma value). Merely as an illustrativenon-limiting example, first re-projected background image dataassociated with a first pixel position may indicate a first brightnesslevel of sixty-five whereas second re-projected background image dataassociated with a second (e.g., different) pixel position, which isadjacent the first pixel position, may indicate a second brightnesslevel of sixty-six. However, low pass filtering the first re-projectedbackground image data and the second re-projected background image datamay result in first filtered background image data corresponding withthe first pixel position and second filtered background image datacorresponding with the second pixel position indicating the samefiltered background brightness level (e.g., luma value). In other words,at least in some instances, filtering re-projected background image datamay result in captured background brightness levels being rounded to acoarser granularity, which, at least in some instances, may facilitatereducing the number of different operational parameter sets associatedwith the active area and, thus, the number of different tone mapping tobe applied in a frame of augmented reality image content.

As such, in some embodiments, an electronic system (e.g., imageprocessing circuitry and/or background analysis block) may determine alocal tone map grid for a frame based at least in part on analysis offiltered background image data corresponding with background imagecontent over which an active region of a display panel is expected todisplay augmented reality image content. In particular, the electronicsystem may analyze the filtered background image data to identify one ormore grid zones in the active region that each groups together adjacentpixel positions associated with the same filtered background brightnesslevel. To help illustrate, continuing with the above example, theelectronic system may include the first pixel position and the secondpixel position, which is adjacent the first pixel position, in the samegrid zone of the local tone map grid due to a first filtered backgroundbrightness level indicated in the first filtered background image datamatching a second filtered background brightness level indicated in thesecond background filtered image data.

In other words, since an ambient lighting metric is indicative ofaverage background brightness level, pixel positions in the same gridzone may be associated with the same perceived background brightnessmetric. In fact, in some embodiments, each pixel position in a grid zonemay be associated with the same set of operational parameters. In otherwords, in some such embodiments, a tone mapping block may apply the sametone mapping (e.g., target tone map look-up-table) to input augmentedreality image data corresponding with each pixel position in a gridzone, for example, while applying a different tone mapping to inputaugmented reality image data corresponding with a pixel position in adifferent grid zone.

As such, to facilitate appropriately tone mapping input augmentedreality image data, in some embodiments, the tone mapping block maydetermine (e.g., identify) a grid zone that includes a correspondingpixel position. In some embodiments, a frame of augmented reality imagedata may be written to display pixels and, thus, processed in rasterorder. Accordingly, in such embodiments, the electronic system (e.g.,image processing circuitry and/or tone mapping block) may determine apixel position corresponding with augmented reality image data based atleast in part on its processing order relative to other augmentedreality image data in the same frame, for example, in view of pixeldimensions a display panel and/or an active region of the display panelthat will be used to display the frame of augmented reality imagecontent.

Based at least in part on the grid zone including a pixel positioncorresponding with input augmented reality image data, the tone mappingblock may determine (e.g., identify and/or select) a target tone mapping(e.g., tone map look-up-table) associated with the grid zone and/or aset of operational parameters corresponding with the grid zone. Asdescribed above, the tone mapping block may apply the target tonemapping to input color component brightness levels indicated in theinput augmented reality image data to determine corresponding outputcolor component brightness levels to be indicated in output (e.g.,display, processed, and/or tone mapped) augmented reality image data. Inthis manner, as will be described in more detail below, the techniquesdescribed in the present disclosure may facilitate adaptively (e.g.,spatially) varying tone mapping applied in a frame of augmented realityimage content and/or adaptively (e.g., temporally) varying tone mappingapplied in different frames of augmented reality image content based atleast in part on optical characteristics (e.g., brightness level) ofbackground image content, which, at least in some instances, mayfacilitate improving perceived quality of augmented reality imagecontent presented on a display panel of an electronic system and, thus,an augmented reality experience provided by the electronic system.

To help illustrate, an example of an electronic system 10, whichincludes and/or utilizes one or more display panels 12, is shown in FIG.1 . As will be described in more detail below, in some embodiments, theelectronic system 10 may be any suitable electronic device, such as anaugmented reality (e.g., mixed-reality) headset and/or the like.Additionally or alternatively, the electronic system 10 may be includedin an electrical system, for example, deployed in an automotive vehicle.Thus, it should be noted that FIG. 1 is merely one example of aparticular implementation and is intended to illustrate the types ofcomponents that may be present in an electronic system 10.

In addition to the one or more display panels 12, as depicted, theelectronic system 10 includes one or more input devices 14, one or moreinput/output (I/O) ports 16, a processor core complex 18 having one ormore processors or processor cores, main memory 20, one or more storagedevices 22, a network interface 24, a power supply 26, image processingcircuitry 27, and one or more optical sensors 28. The various componentsdescribed in FIG. 1 may include hardware elements (e.g., circuitry),software elements (e.g., a tangible, non-transitory computer-readablemedium storing instructions), or a combination of both hardware andsoftware elements. It should be noted that the various depictedcomponents may be combined into fewer components or separated intoadditional components. For example, the main memory 20 and a storagedevice 22 may be included in a single component. Additionally oralternatively, the image processing circuitry 27 may be included in theprocessor core complex 18 or the display panel 12.

As depicted, the processor core complex 18 is operably coupled with mainmemory 20 and the storage device 22. As such, in some embodiments, theprocessor core complex 18 may execute instruction stored in main memory20 and/or a storage device 22 to perform operations, such as generatingimage data. Additionally or alternatively, the processor core complex 18may operate based on circuit connections formed (e.g., programmed)therein. As such, in some embodiments, the processor core complex 18 mayinclude one or more general purpose microprocessors, one or moreapplication specific processors (ASICs), one or more field programmablelogic arrays (FPGAs), or any combination thereof.

In addition to instructions, in some embodiments, the main memory 20and/or the storage device 22 may store data, such as image data. Thus,in some embodiments, the main memory 20 and/or the storage device 22 mayinclude one or more tangible, non-transitory, computer-readable mediathat store instructions executable by processing circuitry, such as theprocessor core complex 18 and/or the image processing circuitry 27,and/or data to be processed by the processing circuitry. For example,the main memory 20 may include random access memory (RAM) and thestorage device 22 may include read only memory (ROM), rewritablenon-volatile memory, such as flash memory, hard drives, optical discs,and/or the like.

As depicted, the processor core complex 18 is also operably coupled withthe network interface 24. In some embodiments, the network interface 24may enable the electronic system 10 to communicate with a communicationnetwork and/or another electronic system 10. For example, the networkinterface 24 may connect the electronic system 10 to a personal areanetwork (PAN), such as a Bluetooth network, a local area network (LAN),such as an 802.11x Wi-Fi network, and/or a wide area network (WAN), suchas a 4G or LTE cellular network. In other words, in some embodiments,the network interface 24 may enable the electronic system 10 to transmitdata (e.g., image data) to a communication network and/or receive datafrom the communication network.

Additionally, as depicted, the processor core complex 18 is operablycoupled to the power supply 26. In some embodiments, the power supply 26may provide electrical power to operate the processor core complex 18and/or other components in the electronic system 10, for example, viaone or more power supply rails. Thus, the power supply 26 may includeany suitable source of electrical power, such as a rechargeable lithiumpolymer (Li-poly) battery and/or an alternating current (AC) powerconverter.

Furthermore, as depicted, the processor core complex 18 is operablycoupled with one or more I/O ports 16. In some embodiments, the I/Oports 16 may enable the electronic system 10 to interface with anotherelectronic system 10. For example, a portable storage device may beconnected to an I/O port 16, thereby enabling the electronic system 10to communicate data, such as image data, with the portable storagedevice.

Moreover, as depicted, the processor core complex 18 is operably coupledwith one or more optical sensors 28. As in the depicted example, theoptical sensors 28 may include one or more ambient light sensors 32. Aswill be described in more detail below, in some embodiments, an ambientlight sensor 32 may be implemented and/or operated to determine (e.g.,generate and/or output) an ambient lighting metric indicative of averagebrightness level (e.g., luma value) of background (e.g., environmentaland/or ambient) light, for example, spatially averaged over an imageframe and/or temporally averaged over multiple (e.g., successively)image frames. Additionally, as in the depicted example, the opticalsensors 28 may include one or more image sensors 30, such as one or morecameras. As will be described in more detail below, in some embodiments,an image sensor 30 may be implemented and/or operated to determine(e.g., capture, generate, and/or output) background image dataindicative of brightness levels (e.g., luma value) at specific locationsin a frame of background image content.

As depicted, the processor core complex 18 is also operably coupled withone or more input devices 14. In some embodiments, an input device 14may enable a user to interact with the electronic system 10. Forexample, the input devices 14 may include one or more buttons, one ormore keyboards, one or more mice, one or more trackpads, and/or thelike. Additionally, in some embodiments, the input devices 14 mayinclude touch sensing components implemented on the display panel 12. Insuch embodiments, the touch sensing components may receive user inputsby detecting occurrence and/or position of an object contacting thedisplay surface of the display panel 12.

In addition to enabling user inputs, the display panel 12 may facilitateproviding visual representations of information by displaying one ormore images (e.g., image frames or pictures). For example, the displaypanel 12 may display a graphical user interface (GUI) of an operatingsystem, an application interface, text, a still image, or video content.To facilitate displaying images, as will be described in more detailbelow, the display panel 12 may include driver (e.g., control)circuitry—namely a scan driver and a data driver—and one or more displaypixels.

As described above, a display panel 12 may display an image bycontrolling light emission from its display pixels based at least inpart on corresponding image data, which is indicative of targetluminance (e.g., brightness level and/or grayscale level) of the displaypixels in a corresponding image. In some embodiments, image data may begenerated by an image source, such as the processor core complex 18, agraphics processing unit (GPU), and/or an image sensor. Additionally oralternatively, image data may be received from another electronic system10, for example, via the network interface 24 and/or an I/O port 16.Moreover, in some embodiments, a display panel 12 may be implemented(e.g., deployed) on a light-transmissive viewing surface of theelectronic system 10, for example, to enable the electronic system 10 toprovide an augmented reality experience.

To help illustrate, an example electronic system 10—namely an augmentedreality headset (e.g., glasses) system 10A—is shown in FIGS. 2 and 3 .In particular, FIG. 2 shows the augmented reality headset system 10Abeing worn by a user 34. On the other hand, FIG. 3 shows an example ofimage frames, which includes augmented reality (e.g., virtual) imagecontent 36 overlaid on background (e.g., real) image content 38, viewedfrom the perspective of the user 34. However, it should be appreciatedthat the depicted examples are merely intended to illustrative and notlimiting.

As in the example depicted in FIG. 2 , the augmented reality headsetsystem 10A may include multiple light-transmissive viewing surfaces(e.g., lenses) 40. In particular, the augmented reality headset system10A includes a first light-transmissive viewing surface 40A, which mayenable a first (e.g., right) eye 42A of the user 34 to visually perceivebackground image content 38, such as the frame of first background imagecontent 38A shown in FIG. 3 . The augmented reality headset system 10Aalso includes a second light-transmissive viewing surface 40B, which mayenable a second (e.g., left) eye 42B of the user 34 to visually perceivebackground image content 38, such as the frame of second backgroundimage content 38B shown in FIG. 3 . As in the example of FIG. 3 , thefirst background image content 38A viewed through the firstlight-transmissive viewing surface 40A may be spatially offset from thesecond background image content 38B viewed through the secondlight-transmissive viewing surface 40B, for example, due to spatialoffset between the user's first eye 42A and the user's second eye 42B.

Additionally, as in the example depicted in FIG. 2 , the augmentedreality headset system 10A may include multiple optical sensors 28implemented (e.g., deployed) proximate its light-transmissive viewingsurfaces 40. In particular, the augmented reality headset system 10Aincludes a first optical sensor 28A proximate the firstlight-transmissive viewing surface 40A and a second optical sensor 28Bproximate the second light-transmissive viewing surface 40B. In someembodiments, the first optical sensor 28A and/or the second opticalsensor 28B may be an image sensor 30 that captures a frame of backgroundimage content 38 by generating captured background image data indicativeof optical (e.g., visual) characteristics, such as color and/orbrightness level, at one or more specific locations in the backgroundimage content 38. Additionally or alternatively, the first opticalsensor 28A and/or the second optical sensor 28B may be an ambient lightsensor 32 that determines (e.g., generates and/or outputs) an ambientlighting metric indicative of average (e.g., mean) brightness level(e.g., luma value) of background (e.g., environmental and/or ambient)light.

Furthermore, as in the example depicted in FIG. 2 , the augmentedreality headset system 10A may include multiple display panels 12implemented (e.g., deployed) on the light-transmissive viewing surfaces(e.g., lenses) 40. In particular, the augmented reality headset system10A may include a first display panel 12A implemented on the firstlight-transmissive viewing surface 40A to enable actively displayingaugmented reality image content 36, such as the frame of first augmentedreality image content 36A shown in FIG. 3 . The augmented realityheadset 10A may also include a second display panel 12B implemented onthe second light-transmissive viewing surface 40B to enable activelydisplaying augmented reality image content 36, such as the frame ofsecond augmented reality image content 36B shown in FIG. 3 .

In this manner, an augmented reality headset system 10A may beimplemented to provide an augmented reality experience. However, itshould again be appreciated that the depicted examples are merelyintended to be illustrative and not limiting. For example, in otherembodiments, a display panel 12 may be implemented with anon-rectangular shape and/or implemented across an entirelight-transmissive viewing surface 40. Moreover, other types ofelectronic systems 10 may additionally or alternatively be implementedand/or operated to provide an augmented reality experience in accordancewith the techniques described in the present disclosure.

To help illustrate, another example an electronic system 10—namely aheads-up display system 10B—is shown in FIG. 4 . As depicted, theheads-up display system 10B is deployed in an automotive vehicle 44, forexample, as part of its electrical system. However, it should beappreciated that the depicted example is merely intended to illustrativeand not limiting.

As depicted, the heads-up display system 10B includes alight-transmissive viewing surface (e.g., windshield) 40C, which mayenable a user 34 (e.g., driver or rider) to visually perceive backgroundimage content 38, such as another automotive vehicle 44 and/or a road onwhich the automotive vehicle 44 is traveling. Additionally, as in thedepicted example, the heads-up display system 10B may include one ormore optical sensors 28C, such as an image sensor 30 and/or an ambientlight sensor 32, deployed proximate the light-transmissive viewingsurface 40C.

Furthermore, as depicted, the heads-up display system 10B includes adisplay panel 12C. As in the depicted example, the display panel 12C maybe implemented and/or operated to display augmented reality imagecontent 36C, such as a visual representation of current speed of theautomotive vehicle 44 and/or a map. In some embodiments, the displaypanel 12C may be integrated with the light-transmissive viewing surface40C. In other embodiments, the display panel 12C may be separate fromthe light-transmissive viewing surface 40C, for example, such that thedisplay panel 12C is implemented between the user 34 and thelight-transmissive viewing surface 40C.

In this manner, a heads-up display system 10B may be implemented toprovide an augmented reality experience. In particular, as describedabove, an electronic system 10 may provide an augmented realityexperience by actively displaying augmented reality image content 36based at least in part on corresponding augmented reality image datasuch that the augmented reality image content is perceived as beingoverlaid on background image content 38 viewed through alight-transmissive viewing surface 40. However, as at least in someinstances, perception of augmented reality image content 36 and, thus,perceived quality of an augmented reality experience provided by theelectronic system 10 may vary with optical (e.g., visual)characteristics of background image content 38. As such, to facilitateimproving augmented reality experience, in some embodiments, imageprocessing circuitry 27 in the electronic system 10 may be implementedand/or operated to process (e.g., adjust) augmented reality image databased at least in part on expected optical characteristics of thebackground image content 38 before the augmented reality image data isused to display corresponding augmented reality image content 36.

To help illustrate, an example of a portion 46 of an electronic system10, which includes image processing circuitry 27, is shown in FIG. 5 .As in the depicted example, the image processing circuitry 27 may becommunicatively coupled between an augmented reality (AR) image source48 and a display panel 12. Additionally, as in the depicted example, theimage processing circuitry 27 may be communicatively coupled to one ormore image sensors 30, one or more ambient light sensors 32, and one ormore controllers 50. However, it should be appreciated that the depictedexample is merely intended to illustrative and not limiting.

In some embodiments, a controller 50 may generally control operation ofthe augmented reality image source 48, the image processing circuitry27, the display panel 12, the one or more image sensors 30, the one ormore ambient light sensors 32, or any combination thereof. Althoughdepicted as a single controller 50, in other embodiments, one or moreseparate controllers 50 may be used to control operation of theaugmented reality image source 48, the image processing circuitry 27,the display panel 12, the one or more image sensors 30, the one or moreambient light sensors 32, or any combination thereof. To facilitatecontrolling operation, as in the depicted example, the controller 50 mayinclude one or more controller processors (e.g., processing circuitry)52 and controller memory 54.

In some embodiments, the controller processor 52 may be included in theprocessor core complex 18 and/or separate processing circuitry and thecontroller memory 54 may be included in main memory 20, a storage device22, and/or a separate, tangible, non-transitory computer-readablemedium. Additionally, in some embodiments, the controller processor 52may execute instructions and/or process data stored in the controllermemory 54 to control operation of the augmented reality image source 48,the image processing circuitry 27, the display panel 12, the one or moreimage sensors 30, and/or the one or more ambient light sensors 32. Inother embodiments, the controller processor 52 may be hardwired withinstructions that, when executed, control operation of the imageprocessing circuitry 27, the display panel 12, the one or more imagesensors 30, the one or more ambient light sensors 32, and/or theaugmented reality image source 48.

Generally, the augmented reality (AR) image source 48 may be implementedand/or operated to generate source (e.g., input or original) augmentedreality image data 56 corresponding with augmented reality image content36 to be displayed on the display panel 12. Thus, in some embodiments,the augmented reality image source 48 may be included in the processorcore complex 18, a graphics processing unit (GPU), an image sensor(e.g., camera) 30, and/or the like. To facilitate displaying images, asin the depicted example, the display panel 12 may include one or moredisplay pixels 58, which each includes one or more color componentsub-pixels, and driver circuitry, which includes a scan driver 60 and adata driver 62. For example, each display pixel 58 implemented on adisplay panel 12 may include a red component sub-pixel, a blue componentsub-pixel, and a green component sub-pixel. As another example, adisplay panel 12 may include a first set (e.g., half) of display pixels58, which each include a red component sub-pixel and a green componentsub-pixel, and a second set (e.g., half) of display pixels 58, whicheach includes a blue component sub-pixel and a green componentsub-pixel. In some embodiments, one or more display pixels 58implemented on a display panel 12 may include a white componentsub-pixel.

As described above, a display panel 12 may display an image byappropriately controlling light emission from its display pixels 58.Generally, light emission from a display pixel 58 may vary with themagnitude of electrical energy stored therein. For example, in someinstances, a display pixel 58 may include a light emissive element, suchas an organic light-emitting diode (OLED), that varies its lightemission with current flow therethrough, a current control switchingdevice (e.g., transistor) coupled between the light emissive element anda pixel power (e.g., VDD) supply rail, and a storage capacitor coupledto a control (e.g., gate) terminal of the current control switchingdevice. As such, varying the amount of energy stored in the storagecapacitor may vary voltage applied to the control terminal of thecurrent control switching device and, thus, magnitude of electricalcurrent supplied from the pixel power supply rail to the light emissiveelement of the display pixel 58.

However, it should be appreciated that discussion with regard to OLEDdisplay pixels 58 and OLED display panels 12 is merely intended to beillustrative and not limiting. In other words, the techniques describedin the present disclosure may be applied to and/or adapted for othertypes of display panels 12, such as a liquid crystal display (LCD)panels 12 and/or a micro light-emitting diode (LED) display panels 12.In any case, since light emission from a display pixel 58 generallyvaries with electrical energy storage therein, to display an image, adisplay panel 12 may write a display pixel 58 at least in part bysupplying an analog electrical (e.g., voltage and/or current) signal tothe display pixel 58, for example, to charge and/or discharge a storagecapacitor implemented in the display pixel 58.

To facilitate selectively writing its display pixels 58, in someembodiments, a display panel 12 may be implemented such that each of itsdisplay pixels 58 is coupled to the scan driver 60 via a correspondingscan line and to the data driver 62 via a corresponding data line. Forexample, to write a row of display pixels 58, the scan driver 60 mayoutput an activation (e.g., logic high) control signal to acorresponding scan line that causes each display pixel 58 coupled to thescan line to electrically couple its storage capacitor to acorresponding data line. Additionally, the data driver 62 may output ananalog electrical signal to each data line coupled to an activateddisplay pixel 58 to control the amount of electrical energy stored inthe display pixel 58 and, thus, resulting light emission (e.g.,perceived luminance and/or perceived brightness).

As described above, image data corresponding with an image may beindicative of target luminance (e.g., grayscale level and/or brightnesslevel) at one or more specific points (e.g., image pixels) in the image,for example, by indicating color component brightness (e.g., grayscale)levels that are scaled by a panel brightness setting. In other words,the image data may correspond with a pixel position and, thus, indicatetarget luminance of a corresponding display pixel 58 implemented at thepixel position on the display panel 12. For example, the image data mayinclude red component image data indicative of target luminance of a redcomponent sub-pixel in the display pixel 58, blue component image dataindicative of target luminance of a blue component sub-pixel in thedisplay pixel 58, green component image data indicative of targetluminance of a green component sub-pixel in the display pixel 58, whitecomponent image data indicative of target luminance of a white componentsub-pixel in the display pixel, or any combination thereof. As such, todisplay an image, the display panel 12 may control supply (e.g.,magnitude and/or duration) of analog electrical signals from its datadriver 62 to its display pixels 58 based at least in part oncorresponding image data. For example, to display augmented realityimage content 36, the display panel 12 may control supply of analogelectrical signals from its data driver 62 to color component sub-pixelsin one or more of its display pixels 58 based at least in part oncorresponding color component brightness levels indicated in augmentedreality image data.

However, to facilitate improving perceived image quality, imageprocessing circuitry 27 may be implemented and/or operated to process(e.g., adjust) image data before the image data is used to display acorresponding image on the display panel 12. Thus, in some embodiments,the image processing circuitry 27 may be included in the processor corecomplex 18, a display pipeline (e.g., chip or integrated circuitdevice), a timing controller (TCON) in the display panel 12, or anycombination thereof. Additionally or alternatively, the image processingcircuitry 27 may be implemented as a system-on-chip (SoC).

As in the depicted example, the image processing circuitry 27 may beimplemented and/or operated to process source augmented reality (AR)image data 56 output from the augmented reality image source 48. In someembodiments, the image processing circuitry 27 may directly receive thesource image data from the augmented reality image source 48.Additionally or alternatively, the source augmented reality image data56 output from the augmented reality image source 48 may be stored in atangible, non-transitory, computer-readable medium, such as main memory20, and, thus, the image processing circuitry 27 may receive (e.g.,retrieve) the source augmented reality image data from the tangible,non-transitory, computer-readable medium, for example, via a directmemory access (DMA) technique.

The image processing circuitry 27 may process the source augmentedreality image data 56 to generate display (e.g., processed or output)augmented reality (AR) image data 64, for example, which adjusts targetluminances to compensate for expected optical characteristics ofbackground image content 38, ambient lighting conditions, pixel (e.g.,sub-pixel) layout on the display panel 12, burn-in on the display panel12, expected response of the display panel 12, or any combinationthereof. The display augmented reality image data 64 may be supplied(e.g., output) to the display panel 12 to enable display panel 12 todisplay corresponding augmented reality image content 36, for example,overlaid on background image content 38. Due to the processing (e.g.,compensation) performed by the image processing circuitry 27, at leastin some instances, displaying augmented reality image content 36 basedon corresponding display (e.g., processed) augmented image data 64 mayfacilitate improving perceived quality of the augmented reality imagecontent 36 and, thus, augmented reality experience, for example,compared to displaying the augmented reality image content 36 directlyusing corresponding source augmented reality image data 56.

In some embodiments, the image processing circuitry 27 may be organizedinto one or more image processing blocks (e.g., circuitry groups). Forexample, the image processing circuitry 27 may include a tone mappingblock 66 implemented and/or operated to process augmented reality imagedata at least in part by tone mapping to adjust one or more targetbrightness (e.g., grayscale) levels indicated in the augmented realityimage data. In particular, as will be described in more detail below, tofacilitate improving perceived image quality, the tone mapping block 66may adaptively adjust tone mapping applied to augmented reality imagedata based at least in part on optical (e.g., visual) characteristics,such as color and/or brightness level, of background image content 38over which corresponding augmented reality image content 36 is expectedto be overlaid.

To facilitate adaptively adjusting tone mapping based on expectedoptical characteristics of background image content 38, as in thedepicted example, the image processing circuitry 27 may additionallyinclude a background re-projection block 68, a background filteringblock 70, and a background analysis block 72. As in the depictedexample, the background re-projection block 68 may receive backgroundimage data 74, which is indicative of expected optical characteristics,such as brightness level (e.g., luma value), at one or more specificlocations in background image content 38, output from an image sensor30. In other words, the background re-projection block 68 may receivebackground image data 74 captured by the image sensor 30.

However, as described above, an image sensor 30 is often spatiallyoffset from an expected location of a user's eye 42. As such, tofacilitate determining optical characteristics of background imagecontent 38 on which augmented reality image content 36 is expected to beoverlaid, the background re-projection block 68 may re-project thecaptured background image data 74 to compensate for the spatial offsetbetween the image sensor 30 and the expected location of the user's eye42. In other words, the background re-projection block 68 may re-projectthe captured background image data 74 from the perspective of the imagesensor 30 to the expected visual perspective of the user's eye 42.

To help illustrate, an example of a frame of captured background imagecontent 38C is shown in FIG. 6 . Additionally, an example of a frame ofre-projected background image content 38R, which results fromre-projecting the captured background image content 38C of FIG. 6 , isshown in FIG. 7 . However, it should be appreciated that the depictedexamples are merely intended to be illustrative and not limiting.

With regard to FIG. 6 , the captured background image content 38C maycorrespond with the first background image content 38A viewed by auser's first eye 42A through the first light-transmissive viewingsurface 40A of FIG. 3 and the second background image content 38B viewedby a user's second eye 42B through the second light-transmissive viewingsurface 40B of FIG. 3 . However, as depicted, the captured backgroundimage content 38C of FIG. 6 has a larger field of view (e.g., viewingangle) compared to the field of view provided by the light-transmissiveviewing surfaces 40 of FIG. 3 . Accordingly, in some embodiments, there-projected background image content 38R may be generated by croppingand/or resizing the captured background image content 38C to re-projectthe captured background image content 38C to the expected visualperspective of a user's eye 42.

In fact, in some embodiments, the same captured background image content38C may be re-projected to generate multiple different versions ofre-projected background image content 38R. For example, firstre-projected background image content 38R may be determined byre-projecting the captured background image content 38C from theperspective of an image sensor 30 to the expected visual perspective ofthe user's first eye 42A and second re-projected background imagecontent 38R may be determined by re-projecting the captured backgroundimage content 38C from the perspective of the image sensor 30 to theexpected visual perspective of the user's second eye 42B. Due to thespatial offset between the user's eyes 42, the first re-projectedbackground image content 38R may differ from the second re-projectedbackground image content 38R and, thus, first re-projected backgroundimage data 74 corresponding with the first re-projected background imagecontent 38R may differ from second re-projected background image data 74corresponding with the second re-projected background image content 38R.

Returning to the image processing circuitry 27 of FIG. 5 , thebackground filtering block 70 may receive background image data 74output from the background re-projection block 68. In other words, thebackground filtering block 70 may receive re-projected background imagedata 74 corresponding with a frame of re-projected background imagecontent 38R. As will be described in more detail below, in someembodiments, the tone mapping block 66 may apply different tone mappingsfor different background brightness levels (e.g., luma values). In otherwords, at least in some instances, the number of different tone mappingsto be applied by image processing circuitry 27 in a frame of augmentedreality image content 36 and, thus, operational efficiency of the imageprocessing circuitry 27 may vary with the number of different brightnesslevels indicated in background image data 74 of a corresponding frame ofbackground image content 38.

Accordingly, to facilitate improving operational efficiency, in someembodiments, the background filtering block 70 may be implemented and/oroperated to filter re-projected background image data 74. For example,the background filtering block 70 may low pass filter the re-projectedbackground image data 74 to determine a corresponding frame of filteredbackground image content 38. Thus, at least in some instances, thenumber of different background brightness levels indicated in filteredbackground image data 74 may be less than the number indicated incorresponding re-projected background image data 74.

To help illustrate, an example of filtered background image content 38Fis shown in FIG. 8 . In particular, the filtered background imagecontent 38F of FIG. 8 may result from filtering re-projected backgroundimage data 74 corresponding with the re-projected background imagecontent 38R of FIG. 7 . However, it should be appreciated that thedepicted examples are merely intended to be illustrative and notlimiting.

In fact, in some embodiments, filtering strength may be adaptivelyadjusted to balance (e.g., optimize) tradeoff between operationalefficiency and perceived quality of augmented reality image content 36.For example, reducing filtering strength may result in a frame offiltered background image content 38F more closely resembling acorresponding frame of re-projected background image content 38R, which,at least in some instances, may facilitate improving the ability of tonemapping to compensate for actual optical characteristics of backgroundimage content 38. On the other hand, increasing filtering strength mayfacilitate reducing the number of different brightness levels (e.g.,luma values) indicated in filtered background image data 74, which, atleast in some instances, may reduce the number of different tonemappings applied in a frame of augmented reality image content 36.

Returning to the image processing circuitry 27 of FIG. 5 , thebackground analysis block 72 may receive background image data 74 outputfrom the background filtering block 70. In other words, the backgroundanalysis block 72 may receive filtered background image data 74corresponding with a frame of filtered background image content 38F. Insome embodiments, a time alignment block 76 may be communicativelycoupled between the background filtering block 70 and the backgroundanalysis block 72 and, thus, filtered background image data 74 may besupplied to the time alignment block 76 before being supplied to thebackground analysis block 72. In particular, in some embodiments, thetime alignment block 76 may be implemented and/or operated to facilitatesynchronizing (e.g., time aligning) operation of the background analysisblock 72 with operation of the tone mapping block 66, for example, bydelaying supply of the filtered background image data 74 to thebackground analysis block 72.

In addition to background image data 74, as in the depicted example, thebackground analysis block 72 may receive an ambient lighting metric 78,which is indicative of an average (e.g., mean) brightness level (e.g.,luma value) of background (e.g., ambient and/or environmental) light,output from an ambient light sensor 32. Based at least in part on thebackground image data 74 and the ambient lighting metric 78, thebackground analysis block 72 may determine a perceived backgroundbrightness metric 80, which is indicative of brightness level ofbackground image content 38 that a user's eye 42 is expected to perceiveat a pixel position corresponding with augmented reality image content36 that is concurrently input to the tone mapping block 66.

However, in some embodiments, an electronic system 10 may be implementedand/or operated to adaptively adjust tint strength applied on one ormore of its light-transmissive viewing surfaces 40. Merely as anillustrative non-limiting example, a liquid crystal (LC) layer may beimplemented on a light-transmissive viewing surfaces 40, therebyenabling the electronic system 10 to control the amount of light thatpasses through the light-transmissive viewing surface 40 at least inpart by controlling orientation of liquid crystals in the liquid crystallayer. For example, in a brighter environment, the electronic system 10may increase tint strength applied on the light-transmissive viewingsurface 40, thereby reducing the amount of light that passes through thelight-transmissive viewing surface 40. Conversely, in a darkerenvironment, the electronic system 10 may decrease tint strength appliedon the light-transmissive viewing surface 40, thereby increasing theamount of light that passes through the light-transmissive viewingsurface 40. In other words, tint strength applied on alight-transmissive viewing surface 40 may affect the brightness level ofbackground image content 38 actually perceived by a user's eye 42.

To facilitate accounting (e.g., compensating) for tint strength, in someembodiments, the background analysis block 72 may additionally receive atint strength parameter 82, which is indicative of tint strengthexpected to be applied on a light-transmissive viewing surface 40 whileaugmented reality image content 36 is being displayed. In this manner,the background analysis block 72 may determine a tint compensatedperceived background brightness metric 80 based at least in part onbackground image data 74, an ambient lighting metric 78, and the tintstrength parameter 82. For example, in some embodiments, the backgroundanalysis block 72 may determine an uncompensated perceived backgroundbrightness metric 80, which is indicative of brightness level ofbackground image content 38 expected to be perceived by a user's eye 42when the light-transmissive viewing surface 40 is not tinted (e.g.,maximum light-transmissiveness). The background analysis block 72 maydetermine a tint compensated perceived background brightness metric 80by scaling the uncompensated perceived background brightness metric 80based on the tint strength parameter 82. For example, the backgroundanalysis block 72 may scale the uncompensated perceived backgroundbrightness metric 80 by an inverse of the tint strength parameter 82,thereby resulting in a higher (e.g., brighter) tint compensatedperceived background brightness metric 80 when tint strength is weakerand a lower (e.g., darker) tint compensated perceived backgroundbrightness metric 80 when tint strength is stronger.

In addition to perceived background brightness metrics 80, in someembodiments, the background analysis block 72 may determine a local tonemap grid 84 for a frame of augmented reality image content 36 based atleast in part on analysis of background image content 38 on which theaugmented reality image content 36 is expected to be overlaid. Inparticular, the local tone map grid 84 may include one or more gridzones, which are each associated with an independently controllable tonemapping. In other words, in some embodiments, the tone mapping block 66may apply the same tone mapping at each pixel position in a grid zone,for example, while applying a different tone mapping at a pixel positionin a different grid zone.

As such, efficiency with which the image processing circuitry 27processes a frame of augmented reality image content 36 may be dependentat least in part on the number of grid zones included in a correspondinglocal tone map grid 84. To facilitate reducing the number of grid zones,in some embodiments, the background analysis block 72 may determine alocal tone map grid 84 corresponding with a frame of augmented realityimage content 36 based at least in part on analysis of filteredbackground image data 74 corresponding with background image content 38over which the augmented reality image content 36 is expected to beoverlaid. Additionally, to facilitate further reducing the number ofnumber of grid zones included in a local tone map grid 84, in someembodiments, the background analysis block 72 may focus on filteredbackground image data 74 corresponding with an active region of adisplay panel 12 that will be used to display augmented reality imagecontent 36.

To help illustrate, an example of a local tone map grid 84A, which isoverlaid on the filtered background image content 38F of FIG. 8 , isshown in FIG. 9 . As depicted, the local tone map grid 84A includesmultiple grid zones 86 in an active region 90 that will be used todisplay augmented reality image content 36 overlaid on background imagecontent 38 corresponding with the filtered background image content 38F.In particular, as in the depicted example, adjacent pixel positionscorresponding with the same filtered background brightness level (e.g.,luma value) may be grouped together in a grid zone 86. For example, afirst block of adjacent pixel positions that each corresponds with afirst filtered background brightness level may be grouped together in afirst grid zone 86A, a second block of adjacent pixel positions thateach corresponds with a second filtered background brightness level maybe grouped together in a second grid zone 86B, and so on.

In this manner, the local tone map grid 84A may divide the active region90 of a display panel 12 into multiple grid zones 86, for example, whichare each associated with an independently controllable tone mapping.However, it should be appreciated that the depicted example is merelyintended to be illustrative and not limiting. In particular, in otherembodiments, a local tone map grid 84 may be determined for an entireframe, for example, such that one or more of its grid zones 86 areoutside an active region 90 of a display panel 12.

Returning to the image processing circuitry 27 of FIG. 5 , in additionto the local tone map grid 84 and perceived background brightnessmetrics 80, the tone mapping block 66 may determine (e.g., receive) aprevious augmented reality content histogram 92. In particular, theprevious augmented reality content histogram 92 may indicate the numberof pixel positions at each of one or more brightness levels and/or oneor more brightness ranges in preceding augmented reality image content36. As such, to facilitate appropriately tone mapping subsequentaugmented reality image content 36, in some embodiments, the imageprocessing circuitry 27 may include an augmented reality contentanalysis block 94 implemented and/or operated to determine a brightnesshistogram for augmented reality image content 36 based at least in parton analysis of corresponding display augmented reality image data 64.For example, the augmented reality content analysis block 94 mayconverted augmented reality image data from color component domains to aluma (e.g., achromatic) domain. The augmented reality content analysisblock 94 may determine the brightness histogram (e.g., previousaugmented reality content histogram 92) at least in part by counting thenumber of pixel positions corresponding with each of one or more lumavalues and/or each of one or more luma ranges.

Based at least in part on a set of operational parameters including theprevious augmented reality content histogram 92, the tone mapping block66 may apply a target tone mapping to input (e.g., source) augmentedreality image data to facilitate determining display augmented realityimage data 64 that accounts (e.g., compensates) for opticalcharacteristics of background image content 38 on which correspondingaugmented reality image content 36 is expected to be overlaid. Tofacilitate tone mapping augmented reality image content 36, in someembodiments, the tone mapping block 66 may include and/or utilize one ormore tone map look-up-tables (LUTs) 96. In fact, to facilitateadaptively accounting for variations in optical characteristics ofbackground image content 38, in some embodiments, the tone mapping block66 may selectively apply different tone map look-up-tables to augmentedreality image data associated with different sets of operationalparameters.

To help illustrate, an example of a tone mapping block 66A, which may beimplemented in image processing circuitry 27 of an electronic system 10,is shown in FIG. 10 . As depicted, the tone mapping block 66A receivesinput augmented reality image data 98. In some embodiments, the inputaugmented reality image data 98 may be source augmented reality imagedata 56 output from an augmented reality image source 48. In otherembodiments, upstream image processing circuitry may process the sourceaugmented reality image data 56 and supply the input augmented realityimage data 98 to the tone mapping block 66A.

Additionally, as in the depicted example, the tone mapping block 66A maytone map the input augmented reality image data 98 to determine (e.g.,generate) output augmented reality image data 100. In some embodiments,the output augmented reality image data 100 may be display augmentedreality image data 64, which will be supplied to a display panel 12 toenable the display panel 12 to display corresponding augmented realityimage content 36. In other embodiments, the output augmented realityimage data 100 may be supplied to downstream image processing circuitry27 for further processing to determine the display augmented realityimage data 64.

As in the depicted example, the output augmented reality image data 100may include color component output image data 102. For example, theoutput augmented reality image data 100 may include red component outputimage data 102, blue component output image data 102, green componentoutput image data 102, white component output image data 102, or anycombination thereof. Additionally, the input augmented reality imagedata 98 may include color component input image data 104. For example,the input augmented reality image data 98 may include red componentinput image data 104, blue component input image data 104, greencomponent input image data 104, white component input image data 104, orany combination thereof. In some embodiments, the input augmentedreality image data 98 may additionally include alpha component inputimage data 105, for example, which is indicative of target transparencyof corresponding augmented reality image content 36.

However, it should be appreciated that the depicted example is merelyintended to illustrative and not limiting. For example, in otherembodiments, target transparency of augmented reality image content 36may instead be indicated by target color component brightness levelsincluded in the color component input image data 104 and, thus, inputaugmented reality image data 98 supplied to a tone mapping block 66 maynot include alpha component input image data 105. Additionally oralternatively, the output augmented reality image data 100 may includealpha component output image data.

As described above, to facilitate improving augmented realityexperience, a tone mapping block 66 (e.g., image processing circuitry27) may adaptively adjust tone mapping applied to augmented realityimage content 36, for example, such that the tone mapping block 66applies different tone mappings to different portions of a frame of theaugmented reality image content 36. Additionally, as described above, atone mapping block 66 may include and/or utilize one or more tone maplook-up-tables (LUTs) 88. In fact, to facilitate adaptively adjustingtone mapping, as in the depicted example, the tone mapping block 66A mayinclude and/or have access to multiple candidate local tone maplook-up-tables (LUTs) 106.

In some embodiments, each of the candidate local tone map look-up-tables(LUTs) 106 may be associated with a different set of operationalparameters. For example, a first candidate local tone map look-up-table106A may be associated with a first set of operational parameters, anNth candidate local tone map look-up-table 106A may be associated withan Nth set of operational parameters, and so on. Additionally, in someembodiments, each set of operational parameters may include one or moreoperational parameters that potentially affect visual perception ofaugmented reality image content 36. For example, a set of operationalparameters associated with input augmented reality image data 98 mayinclude a perceived background brightness metric 80, which is indicativeof brightness level of background image content 38 expected to beperceived by a user 34 through a light-transmissive viewing surface 40,and a previous augmented reality content histogram 92, which isindicative of brightness level in preceding augmented reality imagecontent 36.

Additionally or alternatively, a set of operational parametersassociated with input augmented reality image data 98 may be indicativeof a grid zone 86 that includes a corresponding pixel position. Asdescribed above, a grid zone 86 in a local tone map grid 84 may grouptogether pixel positions associated with the same perceived backgroundbrightness metric 80. Thus, in some embodiments, a set of operationalparameters associated with input augmented reality image data 98 mayinclude a pixel position parameter 110, which identifies a pixelposition associated with the input augmented reality image data 98. Byanalyzing the pixel position corresponding with the input augmentedreality image data 98 in view of the local tone map grid 84, in suchembodiments, the tone mapping block 66A may identify the grid zone 86including the pixel position and, thus, an associated perceivedbackground brightness metric 80.

As such, to facilitate appropriately tone mapping input augmentedreality image data 98, the tone mapping block 66A may select a candidatelocal tone map look-up-table 106 corresponding with an associated set ofoperational parameters as a target local tone map look-up-table 106,which will be used to tone map color component input image data 104included in the input augmented reality image data 98 into colorcomponent output image data 102 to be included in the output augmentedreality image data 100. In particular, in some embodiments, the targetlocal tone map look-up-table 108 may map an input color componentbrightness (e.g., grayscale) level indicated in color component inputimage data 104 to an output color component brightness level indicatedin corresponding color component output image data 102. For example,using the target local tone map look-up-table 108, the tone mappingblock 66A may map a red component input brightness level to a redcomponent output brightness level, a blue component input brightnesslevel to a blue component output brightness level, a green componentinput brightness level to a green component output brightness level, awhite component input brightness level to a white component outputbrightness level, or any combination thereof.

To facilitate selecting a target local tone map look-up-table 108 fromthe candidate local tone map look-up-tables 106, as in the depictedexample, the tone mapping block 66A may include selection circuitry 112.In particular, in some embodiments, the selection circuitry 112 mayoperate to determine a set of operational parameters associated withinput augmented reality image data 98 and select a candidate local tonemap look-up-table 106 associated with the set of operational parametersas the target local tone map look-up-table 108. For example, theselection circuitry 112 may determine (e.g., receive) a set ofoperational parameters including a pixel position parameter 110, whichidentifies a pixel position associated with the input augmented realityimage data 98, a local tone map grid 84 for a frame of correspondingaugmented reality image content 36, a perceived background brightnessmetric 80 associated with the pixel position, alpha component inputimage data 105, which is indicative of target transparency ofcorresponding augmented reality image content 36, a previous augmentedreality content histogram 92, which is indicative of brightness level ina preceding augmented reality image content 36, or any combinationthereof.

By implementing a tone mapping block 66 in image processing circuitry 27of an electronic system 10 in this manner, the image processingcircuitry 27 operate to adaptively vary tone mapping applied atdifferent pixel positions in a frame of augmented reality image content36 and/or in different (e.g., successive) frames of augmented realityimage content 36. For example, as described above, the image processingcircuitry 27 may apply different tone mappings to account (e.g.,compensate) for different brightness levels in background image content38. As described above, at least in some instances, adaptively varyingtone mapping in this manner may facilitate improving perceived qualityof augmented reality image content 36 presented by the electronic system10 and, thus, an augmented reality experience provided by the electronicsystem 10, for example, by enabling a stronger tone mapping to beapplied to augmented reality image content 36 that is expected to beoverlaid on brighter background image content 38, thereby boostingcontrast of the augmented reality image content 36 compared to when theaugmented reality image content 36 is expected to be overlaid on darkerbackground image content 38.

To help further illustrate, an example of a process 114 for operatingimage processing circuitry, which may be implemented in an electronicsystem 10, is described in FIG. 11 . Generally, the process 114 includesreceiving input image data corresponding with augmented reality imagecontent (process block 116) and analyzing a background on which theaugmented reality image content is expected to be overlaid (processblock 118). Additionally, the process 114 includes determining a targetlocal tone mapping based at least in part on the analysis of thebackground and preceding augmented reality image content (process block120) and generating output image data corresponding with the augmentedreality image content by applying the target local tone mapping to theinput image data (process block 122).

Although described in a particular order, which represents a particularembodiment, it should be noted that the process 114 may be performed inany suitable order. Additionally, embodiments of the process 114 mayomit process blocks and/or include additional process blocks. Moreover,in some embodiments, the process 114 may be implemented at least in partby circuit connections formed (e.g., programmed) in image processingcircuitry 27. Additionally or alternatively, the process 114 may beimplemented at least in part by executing instructions stored in atangible, non-transitory, computer-readable medium, such as controllermemory 54, using processing circuitry, such as a controller processor52.

Accordingly, in some embodiments, a controller 50 may instruct imageprocessing circuitry 27 implemented in an electronic system 10 todetermine input augmented reality image data 98, which is to be suppliedto a tone mapping block 66 implemented therein (process block 116). Asdescribed above, in some embodiments, the input augmented reality imagedata 98 may be source augmented reality image data 56 and, thus, outputand/or received from an augmented reality image source 48. In otherembodiments, upstream image processing circuitry 27 may process thesource augmented reality image data 56 to determine the input augmentedreality image data 98 supplied to the tone mapping block 66.

Additionally, the controller 50 may instruct a background analysis block72 implemented in the image processing circuitry 27 to analyze abackground on which augmented reality image content 36 correspondingwith the input augmented reality image data 98 is expected to beoverlaid (process block 118). As described above, the backgroundanalysis block 72 may analyze the background to determine expectedoptical characteristics, such as color and/or brightness level, of aframe of background image content 38. In particular, in someembodiments, the background analysis block 72 may analyze the backgroundto determine a perceived background brightness metric 80, which isindicative of brightness level of background image content 38 expectedto be perceived at a pixel position corresponding with the inputaugmented reality image data 98 (process block 124).

To help illustrate, an example of a process 126 for operating imageprocessing circuitry 27, which may be implemented in an electronicsystem 10, to determine a perceived background brightness metric 80 isdescribed in FIG. 12 . Generally, the process 126 includes determiningan ambient lighting metric (process block 128) and determining capturedbackground image data corresponding with background image content(process block 130). Additionally, the process 126 includes determiningre-projected background image data by re-projecting the capturedbackground image data (process block 132), determining filteredbackground image data by filtering the re-projected background imagedata (process block 134), and analyzing the filtered background imagedata based on the ambient lighting metric to determine a perceivedbackground brightness metric (process block 136).

Although described in a particular order, which represents a particularembodiment, it should be noted that the process 126 may be performed inany suitable order. Additionally, embodiments of the process 126 mayomit process blocks and/or include additional process blocks. Moreover,in some embodiments, the process 126 may be implemented at least in partby circuit connections formed (e.g., programmed) in image processingcircuitry 27. Additionally or alternatively, the process 126 may beimplemented at least in part by executing instructions stored in atangible, non-transitory, computer-readable medium, such as controllermemory 54, using processing circuitry, such as a controller processor52.

Accordingly, in some embodiments, a controller 50 may instruct abackground analysis block 72 implemented in image processing circuitry27 of an electronic system 10 to determine an ambient lighting metric78, which is indicative of an average (e.g., mean) brightness level(e.g., luma value) of background light, for example, spatially averagedover an image frame and/or temporally averaged over multiple (e.g.,successively) image frames (process block 128). As described above, insome embodiments, an ambient lighting metric 78 may be determined (e.g.,measured and/or output) by an ambient light sensor 32. Thus, in suchembodiments, the background analysis block 72 may receive the ambientlight metric 78 output from the ambient light sensor 32.

Additionally, the controller 50 may instruct the image processingcircuitry 27 to determine captured background image data 74corresponding with a frame of background image content 38 (process block130). As described above, in some embodiments, an image sensor 30 maycapture background image content 38 by generating captured backgroundimage data 74, which indicate color component brightness levels at oneor more locations (e.g., points and/or image pixels) in background imagecontent 38. Thus, in such embodiments, the image processing circuitry 27may receive the captured background image data 74 output from the imagesensor 30.

In some embodiments, the electronic system 10 may convert backgroundimage data 74 from a color component domain to a luma domain beforesubsequent processing by its image processing circuitry 27. In otherwords, in such embodiments, the electronic system 10 may combinemultiple color component brightness (e.g., grayscale) levels indicatedin the background image data 74 (e.g., after weighting) to determine acorresponding luma value. For example, when captured using ared-green-blue (RGB) color space, the electronic system 10 may determinethe luma value as a sum of a red component brightness level scaled(e.g., multiplied) by a first coefficient, a blue component brightnesslevel scaled by a second coefficient, and a green component brightnesslevel scaled by a third coefficient. In other embodiments, thebackground image data 74 may be captured using a different color space,such as an International Commission on Illumination (CIE) XYZ colorspace, an International Commission on Illumination (CIE) L*a*b* colorspace, or an IPT color space, and converted to a corresponding lumavalue.

Furthermore, the controller 50 may instruct a background re-projectionblock 68 implemented in the image processing circuitry 27 to determinere-projected background image data 74 by processing the capturedbackground image data 74 to re-project the captured background imagecontent 38C from the perspective of the image sensor 30 to the expectedperspective of a user's eye 42 (process block 132). As described above,in some embodiments, the background re-projection block 68 mayre-project captured background image content 38C at least in part bycropping and/or resizing the captured background image content 38 todetermine re-projected background image content 38R that is expected tobe viewed through a light-transmissive viewing surface 40 of theelectronic system 10. Additionally, as described above, in someembodiments, the background re-projection block 68 may determinemultiple versions of re-projected background image content 38R, forexample, to facilitate accounting for spatial offset between a first eye42A of the user 34 and a second eye 42B of the user 34.

The controller 50 may instruct a background filtering block 70implemented in the image processing circuitry 27 to determine filteredbackground image data 74 by filtering the re-projected background imagedata 74 output from the background re-projection block 68 (process block134). As described above, in some embodiments, the background filteringblock 70 may low pass filter the re-projected background image data 74corresponding with a frame of re-projected background image content 38Rto determine corresponding filtered background image data 74. In otherwords, at least in some such embodiments, filtering multiple differentbackground brightness levels (e.g., luma values) indicated inre-projected background image data 74 may result (e.g., rounded to) inthe same filtered background brightness level. Thus, at least in suchembodiments, the number of different brightness levels indicated infiltered background image content 38F may be less than the numberindicated in corresponding re-projected background image content 38R.

Additionally, the controller 50 may instruct the background analysisblock 72 to determine a perceived background brightness metric 80 basedat least in part on the filtered background image data 74 and theambient lighting metric 78 (process block 136). As described above, aperceived background brightness metric 80 may be indicative ofbackground brightness expected to be perceived through alight-transmissive viewing surface 40 of the electronic system 10.However, as described above, in some embodiments, an electronic system10 may adaptively adjust tint strength applied on one or more of itslight-transmissive viewing surfaces 40, which, at least in someinstances, may affect the background brightness actually perceived by auser 34.

To facilitate accounting for tint strength, in some embodiments, thebackground analysis block 72 may determine an uncompensated perceivedbackground brightness metric 80 based on the filtered background imagedata 74 and the ambient lighting metric 78. The background analysisblock 72 may determine a tint compensated perceived backgroundbrightness metric 80 by scaling the uncompensated perceived backgroundbrightness metric 80 based on a tint strength parameter 82, which isindicative of tint strength expected to be applied on alight-transmissive viewing surface 40 of the electronic system 10. Forexample, the background analysis block 72 may scale the uncompensatedperceived background brightness metric 80 by an inverse of the tintstrength parameter 82, thereby resulting in a higher (e.g., brighter)tint compensated perceived background brightness metric 80 when tintstrength is weaker and a smaller (e.g., darker) tint compensatedperceived background brightness metric 80 when tint strength isstronger.

In this manner, image processing circuitry 27 implemented in anelectronic system 10 may operate to determine one or more perceivedbackground brightness metrics 80 based at least in part on analysis ofexpected background (e.g., real) optical characteristics. Returning tothe process 114 of FIG. 11 , as described above, in some embodiments,the electronic system 10 may additionally determine a local tone mapgrid 84 for a frame of augmented reality image content 36 based at leastin part on analysis of the background over which the augmented realityimage content 36 is expected to be overlaid (process block 138). Forexample, as described above, a local tone map grid 84 may be set suchthat each of its grid zones 86 groups together pixel positionsassociated with approximately the same background opticalcharacteristics.

To help further illustrate, an example of a process 140 for determininga local tone map grid 84 is described in FIG. 13 . Generally, theprocess 140 includes determining an active region to be used to displayaugmented reality image content (process block 142), determiningbackground image data corresponding with the active region (processblock 144), and identifying a grid zone in the active regioncorresponding with a specific background brightness range (process block146). Additionally, the process 140 includes determining whether adifferent background brightness range is present in the active region(decision block 148), identifying another grid zone in the active regioncorresponding with the different background brightness range when thedifferent background brightness range is present in the active region(process block 150), and setting a local tone map grid when a differentbackground brightness range is not present in the active region (processblock 152).

Although described in a particular order, which represents a particularembodiment, it should be noted that the process 140 may be performed inany suitable order. Additionally, embodiments of the process 140 mayomit process blocks and/or include additional process blocks. Moreover,in some embodiments, the process 140 may be implemented at least in partby circuit connections formed (e.g., programmed) in image processingcircuitry 27. Additionally or alternatively, the process 140 may beimplemented at least in part by executing instructions stored in atangible, non-transitory, computer-readable medium, such as controllermemory 54, using processing circuitry, such as a controller processor52.

Accordingly, in some embodiments, a controller 50 may instruct abackground analysis block 72 implemented in image processing circuitry27 of an electronic system 10 to determine (e.g., identify) an activeregion 90 of a display panel 12 that will be used to display augmentedreality image content 36 (process block 142). In particular, asdescribed above, the active region 90 may at least include each pixelposition corresponding with a display pixel 58 that emits light todisplay the augmented reality image content 36. Additionally, asdescribed above, a display panel 12 may control light emission from itsdisplay pixels 58 based at least in part on one or more target colorcomponent brightness levels indicated in corresponding image data.

As such, to facilitate identifying the active region 90, in someembodiments, the background analysis block 72 may analyze augmentedreality image data corresponding with the augmented reality imagecontent 36. For example, the background analysis block 72 may determinethat a pixel position will not be used to actively display augmentedreality image content 36 when each target color component brightnesslevel indicated in corresponding augmented reality image data is zero.On the other hand, the background analysis block 72 may determine that apixel position will actively be used to display augmented reality imagecontent 36 when one or more target color component brightness levels isnon-zero and, thus, should be included in the active region 90.Nevertheless, to facilitate improving operational and/or computationalefficiency, in some embodiments, the background analysis block 72 maydetermine the active region 90 with a rectangular shape and, thus, theactive region 90 in a frame may include one or more pixel positions thatdo not actively display augmented reality image content 36.

Additionally, the controller 50 may instruct the background analysisblock 72 to determine background image data 74 corresponding withbackground image content 38 over which the active region 90 is expectedto be overlaid (process block 144). As described above, in someembodiments, the background analysis block 72 may analyze filteredbackground image data 74 corresponding with the background image content38. Accordingly, in such embodiments, the background analysis block 72may identify filtered background image data 74 corresponding with eachpixel position included in the active region 90.

Furthermore, the controller 50 may instruct the background analysisblock 72 to identify a grid zone 86 corresponding with a specificbackground brightness range in the active region 90 (process block 146).As described above, in some embodiments, filtering multiple differentcaptured background brightness levels (e.g., luma values) may result inthe same filtered background brightness level. In other words, in suchembodiments, each filtered background brightness level (e.g., lumavalue) indicated in the filtered background image data 74 may correspondwith a different range of captured background brightness levels.

Additionally, as described above, a grid zone 86 may group togetherpixel positions associated with approximately the same backgroundoptical characteristics. Thus, in some embodiments, the backgroundanalysis block 72 may group together adjacent pixel positions associatedwith the same filtered background brightness level in a grid zone 86.However, to facilitate improving operational and/or computationalefficiency, in some embodiments, the background analysis block 72 mayidentify each grid zone 86 with a rectangular shape, which, at least insome instances, may result in adjacent pixel positions associated withthe same filtered background brightness level nevertheless beingincluded in different grid zones 86.

The controller 50 may instruct the background analysis block 72 todetermine whether a pixel position in the active region 90 is associatedwith a different background brightness range (decision block 148). Inother words, in some embodiments, the background analysis block 72 maydetermine whether a pixel position in the active region 90 is associatedwith a different filtered background brightness level. When a differentbackground brightness range is present, the controller 50 may instructthe background analysis block 72 to identify another grid zone 86 in theactive region 90 corresponding with the different background brightnessrange (process block 150). In other words, in some embodiments, thebackground analysis block 72 may identify another grid zone 86 in theactive region 90 corresponding with the different filtered backgroundbrightness level.

On the other hand, once a grid zone 86 has been identified for eachbackground brightness range in the active region 90, the controller 50may instruct the background analysis block 72 to set (e.g., finalize)the local tone map grid 84 for a frame including the augmented realityimage content 36 (process block 152). In some embodiments, thebackground analysis block 72 may set the local tone map grid 84 byidentifying pixel positions on a display panel 12 included in each ofits grid zones 86. As such, based at least in part on a pixel positioncorresponding with augmented reality image data, in some embodiments,image processing circuitry 27 may identify a grid zone 86 in whichcorresponding augmented reality image content 36 will be displayed.

Returning to the process 114 of FIG. 11 , based at least in part onanalysis of the background and preceding augmented reality image content36, the tone mapping block 66 implemented in the image processingcircuitry 27 may determine a target local tone mapping to be applied tothe input augmented reality image data 98 (process block 120). Asdescribed above, in some embodiments, the tone mapping block 66 mayperform tone mapping using one or more tone map look-up-tables 88.Accordingly, to facilitate applying the appropriate local tone mapping,in some embodiments, the tone mapping block 66 may determine a targetlocal tone map look-up-table 108, for example, selected from multiplecandidate local tone map look-up-tables 106 based at least in part onthe analysis of the background and the preceding augmented reality imagecontent 36.

To help further illustrate, an example of a process 156 for determininga target local tone map look-up-table 108 is described in FIG. 14 .Generally, the process 156 includes determining candidate local tone maplook-up-tables corresponding with different sets of operationalparameters (process block 158), determining a set of operationalparameters associated with input augmented reality image data (processblock 160), and selecting a candidate local tone map look-up-tablecorresponding with the set of operational parameters as a target localtone map look-up-table (process block 162).

Although described in a particular order, which represents a particularembodiment, it should be noted that the process 156 may be performed inany suitable order. Additionally, embodiments of the process 156 mayomit process blocks and/or include additional process blocks. Moreover,in some embodiments, the process 156 may be implemented at least in partby circuit connections formed (e.g., programmed) in image processingcircuitry 27. Additionally or alternatively, the process 156 may beimplemented at least in part by executing instructions stored in atangible, non-transitory, computer-readable medium, such as controllermemory 54, using processing circuitry, such as a controller processor52.

Accordingly, in some embodiments, a controller 50 may instruct a tonemapping block 66 implemented in image processing circuitry 27 of anelectronic system 10 to determine multiple different candidate localtone map look-up-tables 106 (process block 158). As described above, insome embodiments, each of the different candidate local tone maplook-up-tables 106 may be associated with a different set of operationalparameters. Additionally, the controller 50 may instruct the tonemapping block 66 to determine a set of operational parameters associatedwith input augmented reality image data 98 (process block 160).

As described above, in some embodiments, a set of operational parametersassociated with augmented reality image data may include one or moreoperational parameters that potentially affect visual perception ofcorresponding augmented reality image content 36. Thus, in someembodiments, determining the set of operational parameters associatedwith input augmented reality image data 98 may include determining a(e.g., tint compensated) perceived background brightness metric 80associated with a pixel position corresponding with the input augmentedreality image data 98 (process block 164) and determining a previousaugmented reality content histogram 92 (process block 166). As describedabove, in some embodiments, the tone mapping block 66 may receive theperceived background brightness metric 80 from a background analysisblock 72 implemented in the image processing circuitry 27.

Additionally, as described above, a local tone map grid 84 correspondingwith a frame of augmented reality image content 36 may identify thepixel positions on a display panel 12 that are included in each of itsgrid zones 86. Furthermore, as described above, in some embodiments,each grid zone 86 in a local tone map grid 84 may be associated with aspecific set of operational parameters, for example, including aspecific perceived background brightness metric 80 associated with eachpixel position included therein. Thus, in some embodiments, determiningthe set of operational parameters associated with the input augmentedreality image data 98 may additionally or alternatively includedetermining (e.g., identifying) a pixel position corresponding with theinput augmented reality image data 98 (process block 168) anddetermining (e.g., identifying) a grid zone 86 that includes the pixelposition (process block 170).

As described above, in some embodiments, the electronic system 10 (e.g.,image processing circuitry 27 and/or tone mapping block 66) maydetermine the pixel position corresponding with input augmented realityimage data 98 based at least in part on its processing order relative toother augmented reality image data in the same frame, for example, inview of pixel dimensions a display panel 12 and/or an active region 90of the display panel 12 that will be used to display the frame ofaugmented reality image content 36. Additionally, as described above, byanalyzing the pixel position in view of a local tone map grid 84corresponding with the frame of augmented reality image content 36, thetone mapping block 66 may identify the grid zone 86 corresponding withthe input augmented reality image data 98. In this manner, the tonemapping block 66 may determine a set of operational parametersassociated with each pixel position in the grid zone 86 and, thus, theinput augmented reality image data 98.

Furthermore, in some embodiments, determining the set of operationalparameters associated with the input augmented reality image data 98 mayadditionally or alternatively include determining target transparency ofcorresponding augmented reality image content 36 (process block 172). Asdescribed above, in some embodiments, the tone mapping block 66 maydetermine the target transparency of the corresponding augmented realityimage content 36 based on alpha component input image data 105 includedin the input augmented reality image data 98. Additionally oralternatively, the tone mapping block 66 may determine the targettransparency of the corresponding augmented reality image content 36based on target color component brightness (e.g., grayscale) levelsindicated in the input augmented reality image data 98.

Based on the associated set of operational parameters, the tone mappingblock 66 may select a target local tone map look-up-table 108 from themultiple candidate local tone map look-up-tables 106 (process block162). For example, the tone mapping block 66 may select a firstcandidate local tone map look-up-table 106A as the target local tone maplook-up-table 108 when the input augmented reality image data 98 isassociated with a first set of operational parameters, an Nth candidatelocal tone map look-up-table 106N as the target local tone maplook-up-table 108 when the input augmented reality image data 98 isassociated with a second set of operational parameters, and so on. Inthis manner, a tone mapping block 66 implemented in image processingcircuitry of an electronic system 10 may operate to adaptively determinea target tone mapping to be applied to input augmented reality imagedata 98.

Returning to the process 114 of FIG. 11 , the controller 50 may instructthe tone mapping block 66 to apply the target local tone mapping to theinput augmented reality image data 98 to determine (e.g., generateand/or output) output augmented reality image data 100 (process block122). For example, using the target local tone map look-up-table 108,the tone mapping block 66 may map a target red component brightnesslevel indicated in the input augmented reality image data 98 to a targetred component brightness level to be indicated in the output augmentedreality image data 100, a target blue component brightness levelindicated in the input augmented reality image data 98 to a target bluecomponent brightness level to be indicated in the output augmentedreality image data 100, and/or a target green component brightness levelindicated in the input augmented reality image data 98 to a target greencomponent brightness level to be indicated in the output augmentedreality image data 100. In some embodiments, using the target local tonemap look-up-table 108, the tone mapping block 66 may additionally oralternatively map a target white component brightness level indicated inthe input augmented reality image data 98 to a target white componentbrightness level to be indicated in the output augmented reality imagedata 100.

As described above, in some embodiments, the output augmented realityimage data 100 may be display augmented reality image data 64, which issupplied to a display panel 12 to enable the display panel 12 to present(e.g., display) corresponding augmented reality image content 36. Inother embodiments, the output augmented reality image data may befurther processed by downstream image processing circuitry 27 todetermine the display augmented reality image data 64. Moreover, asdescribed above, in some embodiments, downstream image processingcircuitry 27 (e.g., augmented reality content analysis block 94) mayanalyze the display augmented reality image data 64 to determine aprevious augmented reality content histogram 92, which will be usedduring tone mapping of subsequent augmented reality image content 36. Inthis manner, the techniques described in the present disclosure mayenable an electronic system 10 to adaptively adjusting tone mappingapplied to augmented reality image content 36 based at least in part onexpected background optical characteristics, which, at least in someinstances, may facilitate improving perceived quality of the augmentedreality image content 36 and, thus, an augmented reality experienceprovided by the electronic system 10.

The specific embodiments described above have been shown by way ofexample, and it should be understood that these embodiments may besusceptible to various modifications and alternative forms. It should befurther understood that the claims are not intended to be limited to theparticular forms disclosed, but rather to cover all modifications,equivalents, and alternatives falling within the spirit and scope ofthis disclosure.

It is well understood that the use of personally identifiableinformation should follow privacy policies and practices that aregenerally recognized as meeting or exceeding industry or governmentalrequirements for maintaining the privacy of users. In particular,personally identifiable information data should be managed and handledso as to minimize risks of unintentional or unauthorized access or use,and the nature of authorized use should be clearly indicated to users.

What is claimed is:
 1. An electronic system comprising: a display panelimplemented on a light-transmissive viewing surface of the electronicsystem, wherein the display panel is configured to display a frame ofaugmented reality image content such that the augmented reality imagecontent is perceived as being overlaid on background image contentviewed through the light-transmissive viewing surface and adaptivelyadjust tint strength applied on the light-transmissive viewing surface;and image processing circuitry communicatively coupled to the displaypanel, wherein the image processing circuitry is configured to: receivefirst input augmented reality image data corresponding with a firstpixel position on the display panel; determine an uncompensatedperceived background brightness metric indicative of brightness level ofthe background image content expected to be perceived at the first pixelposition on the display panel when the light-transmissive viewingsurface is not tinted; determine a first perceived background brightnessmetric indicative of a brightness level of the background image contentexpected to be perceived at the first pixel position on the displaypanel during display of the augmented reality image content based atleast in part on captured background image data output from an imagesensor and an ambient lighting metric output from an ambient lightsensor and based at least in part on the tint strength expected to beapplied on the light-transmissive viewing surface while the displaypanel is displaying the frame of augmented reality image content,wherein the first perceived background brightness metric is determinedat least in part by scaling the uncompensated perceived backgroundbrightness metric based on a tint strength expected to be applied on thelight-transmissive viewing surface; determine a first target tonemapping to be applied to the first input augmented reality image databased at least in part on the first perceived background brightnessmetric associated with the first input augmented reality image data; anddetermine display augmented reality image data to be used by the displaypanel to display the augmented reality image content at least in part byapplying the first target tone mapping to the first input augmentedreality image data.
 2. The electronic system of claim 1, wherein theimage processing circuitry is configured to: receive second inputaugmented reality image data corresponding with a second pixel positiondifferent from the first pixel position on the display panel; determinea second perceived background brightness metric indicative of brightnesslevel of the background image content expected to be perceived at thesecond pixel position on the display panel during display of theaugmented reality image content based at least in part on the capturedbackground image data output from the image sensor and the ambientlighting metric output from the ambient light sensor; determine a secondtarget tone mapping different from the first target tone mapping to beapplied to the second input augmented reality image data based at leastin part on the second perceived background brightness metric associatedwith the second input augmented reality image data; and determine thedisplay augmented reality image data to be used by the display panel todisplay the augmented reality image content at least in part by applyingthe second target tone mapping to the second input augmented realityimage data.
 3. The electronic system of claim 2, wherein: the firsttarget tone mapping applied to the first input augmented reality imagedata corresponding with the first pixel position is stronger than thesecond target tone mapping applied to the second input augmented realityimage data corresponding with the second pixel position when the firstperceived background brightness metric associated with the first pixelposition is greater than the second perceived background brightnessmetric associated with the second pixel position; the first target tonemapping applied to the first input augmented reality image datacorresponding with the first pixel position is weaker than the secondtarget tone mapping applied to the second input augmented reality imagedata corresponding with the second pixel position when the firstperceived background brightness metric associated with the first pixelposition is less than the second perceived background brightness metricassociated with the second pixel position; or both.
 4. The electronicsystem of claim 1, wherein the image processing circuitry is configuredto: determine a previous augmented reality content histogram indicativeof brightness level of a preceding frame of augmented reality imagecontent; and determine the first target tone mapping to be applied tothe first input augmented reality image data based at least in part onthe previous augmented reality content histogram.
 5. The electronicsystem of claim 4, wherein the first target tone mapping to be appliedto the first input augmented reality image data is: stronger when theprevious augmented reality content histogram indicates that thepreceding frame of augmented reality image content is brighter; weakerwhen the previous augmented reality content histogram indicates that thepreceding frame of augmented reality image content is darker; or both.6. The electronic system of claim 1, wherein the first target tonemapping to be applied to the first input augmented reality image datais: stronger when the tint strength expected to be applied on thelight-transmissive viewing surface is weaker; weaker when the tintstrength expected to be applied on the light-transmissive viewingsurface is stronger; or both.
 7. The electronic system of claim 1,comprising an augmented reality image source communicatively to theimage processing circuitry, wherein: the augmented reality image sourceis configured to output source augmented reality image datacorresponding with the frame of augmented reality image content; and theimage processing circuitry is configured to process the source augmentedreality image data to determine the first input augmented reality imagedata corresponding with the first pixel position in the frame ofaugmented reality image content.
 8. The electronic system of claim 1,wherein: the electronic system comprises a head-up display systemconfigured to be deployed in an automotive vehicle; and thelight-transmissive viewing surface comprises at least a portion of awindshield of the automotive vehicle.
 9. The electronic system of claim1, wherein the electronic system comprises an augmented reality headsetsystem, a mixed reality headset system, or augmented reality glasses.10. The electronic system of claim 1, wherein the image processingcircuitry is configured to re-project the background image data tospatially relocate the background image data.
 11. An electronic systemcomprising: a display panel implemented on a light-transmissive viewingsurface of the electronic system, wherein the display panel isconfigured to display a frame of augmented reality image content suchthat the augmented reality image content is perceived as being overlaidon background image content viewed through the light-transmissiveviewing surface; and image processing circuitry communicatively coupledto the display panel, wherein the image processing circuitry isconfigured to: receive first input augmented reality image datacorresponding with a first pixel position on the display panel;determine first re-projected background image data at least in part byprocessing the captured background image data output from the imagesensor to re-project a captured frame of the background image contentfrom a perspective of the image sensor to an expected perspective of auser's first eye provided by the light-transmissive viewing surface ofthe electronic system; determine first filtered background image data atleast in part by low pass filtering the first re-projected backgroundimage data; determine a first perceived background brightness metricindicative of a brightness level of the background image contentexpected to be perceived at the first pixel position on the displaypanel during display of the augmented reality image content based atleast in part on the first filtered background image data correspondingwith the first pixel position on the display panel and an ambientlighting metric output from an ambient light sensor; determine a firsttarget tone mapping to be applied to the first input augmented realityimage data based at least in part on the first perceived backgroundbrightness metric associated with the first input augmented realityimage data; and determine display augmented reality image data to beused by the display panel to display the augmented reality image contentat least in part by applying the first target tone mapping to the firstinput augmented reality image data.
 12. The electronic system of claim11, comprising another display panel implemented on anotherlight-transmissive viewing surface of the electronic system, wherein:the other display panel is configured to display the frame of augmentedreality image content such that the augmented reality image content isperceived as being overlaid on the background image content viewedthrough the other light-transmissive viewing surface; and the imageprocessing circuitry is configured to: receive second input augmentedreality image data corresponding with a second pixel position on theother display panel; determine second re-projected background image dataat least in part by processing the captured background image data outputfrom the image sensor to re-project the captured frame of the backgroundimage content from the perspective of the image sensor to an expectedperspective of the user's second eye provided by the otherlight-transmissive viewing surface of the electronic system; determinesecond filtered background image data at least in part by low passfiltering the second re-projected background image data; determine asecond perceived background brightness metric indicative of brightnesslevel of the background image content expected to be perceived at thesecond pixel position on the other display panel based at least in parton the second filtered background image data corresponding with thesecond pixel position on the other display panel and the ambientlighting metric output from the ambient light sensor; determine a secondtarget tone mapping to be applied to the second input augmented realityimage data based at least in part on the second perceived backgroundbrightness metric associated with the second input augmented realityimage data; and determine other display augmented reality image data tobe used by the other display panel to display the augmented realityimage content at least in part by applying the second target tonemapping to the second input augmented reality image data.
 13. Theelectronic system of claim 11, wherein the image processing circuitry isconfigured to: determine a local tone map grid corresponding with theframe of augmented reality image content based at least in part on thefirst filtered background image data, wherein the local tone map gridcomprises a plurality of grid zones that each groups together adjacentpixel positions associated with a same perceived background brightnessmetric; determine a grid zone including the first pixel positioncorresponding with the first input augmented reality image data; anddetermine the first perceived background brightness metric indicative ofthe brightness level of the background image content expected to beperceived at the first pixel position as a perceived backgroundbrightness metric associated with the grid zone including the firstpixel position.
 14. The electronic system of claim 11, wherein the imageprocessing circuitry is configured to: determine a second perceivedbackground brightness metric indicative of brightness level of thebackground image content expected to be perceived at a second pixelposition adjacent the first pixel position on the display panel based atleast in part on the first filtered background image data correspondingwith the second pixel position and the ambient lighting metric outputfrom the ambient light sensor; identify the first pixel position and thesecond pixel position as being included in a first grid zone of a localtone map grid associated with the frame of augmented reality imagecontent when the first perceived background brightness metric associatedwith the first pixel position matches the second perceived backgroundbrightness metric associated with the second pixel position, whereineach pixel position included in the first grid zone of the local tonemap grid is associated with the first target tone mapping; and identifythe second pixel position as being included in a second grid zonedifferent from the first grid zone of the local tone map when the secondperceived background brightness metric associated with the second pixelposition does not match the first perceived background brightness metricassociated with the first pixel position, wherein each pixel positionincluded in the second grid zone of the local tone map grid isassociated with a second target tone mapping different from the firsttarget tone mapping.
 15. A method of operating an electronic systemcomprising: receiving, using processing circuitry implemented in theelectronic system, first augmented reality input image datacorresponding with a first frame of augmented reality image content tobe displayed on a display panel such that the first frame of augmentedreality image content is perceived as being overlaid on background imagecontent viewed through a light transmissive viewing surface of theelectronic system; receiving, using the processing circuitry, firstcaptured background image data output from an image sensor, wherein thefirst captured background image data corresponds with a first capturedframe of the background image content over which the first frame ofaugmented reality image content is expected to be overlaid; determining,using the processing circuitry, first re-projected background image dataat least in part by processing the first captured background image datato re-project the first captured frame of the background image contentfrom a perspective of the image sensor to an expected viewingperspective provided by the light transmissive viewing surface of theelectronic system; determining, using the processing circuitry, firstfiltered background image data at least in part by processing the firstre-projected background image data to low pass filter the firstre-projected background image data; determining, using the processingcircuitry, a first local tone map grid corresponding with the firstframe of augmented reality image content based at least in part on thefirst filtered background image data, wherein the first local tone mapgrid comprises a first plurality of grid zones that are each associatedwith a different target local tone mapping; and determining, using theprocessing circuitry, first display augmented reality image data to beoutput to the display panel to enable the display panel to display thefirst frame of augmented reality image content at least in part by tonemapping the first augmented reality input image data in accordance withthe first local tone map grid.
 16. The method of claim 15, comprising,receiving, an ambient lighting metric output from an ambient lightsensor, wherein determining the first display augmented reality imagedata comprises: determining a perceived background brightness metricindicative of brightness level of the background image content expectedto be perceived at a pixel position on the display panel during displayof the first frame of augmented reality image content based at least inpart on the first filtered background image data corresponding with thepixel position and the ambient lighting metric; determining a previousaugmented reality content histogram indicative of augmented realityimage content brightness level of a previous frame of augmented realityimage content; determining a target tone mapping to be applied to thefirst augmented reality input image data corresponding with the pixelposition on the display panel based at least in part on the perceivedbackground brightness metric associated with the pixel position and theprevious augmented reality content histogram; and determining the firstdisplay augmented reality image data corresponding with the pixelposition on the display panel at least in part by applying the targettone mapping to the first augmented reality input image datacorresponding with the pixel position on the display panel.
 17. Themethod of claim 15, comprising: receiving, using the processingcircuitry implemented in the electronic system, second augmented realityinput image data corresponding with a second frame of augmented realityimage content to be displayed on the display panel such that the secondframe of augmented reality image content is perceived as being overlaidon the background image content viewed through the light transmissiveviewing surface of the electronic system; receiving, using theprocessing circuitry, second captured background image data output fromthe image sensor, wherein the second captured background image datacorresponds with a second captured frame of the background image contentover which the second frame of augmented reality image content isexpected to be overlaid; determining, using the processing circuitry,second re-projected background image data at least in part by processingthe second captured background image data to re-project the secondcaptured frame of the background image content from the perspective ofthe image sensor to the expected viewing perspective provided by thelight transmissive viewing surface of the electronic system; anddetermining, using the processing circuitry, second filtered backgroundimage data at least in part by processing the second re-projectedbackground image data to low pass filter the second re-projectedbackground image data; determining, using the processing circuitry, asecond local tone map grid corresponding with the second frame ofaugmented reality image content based at least in part on the secondfiltered background image data, wherein the second local tone map gridcomprises a second plurality of grid zones and is different from thefirst local tone map grid corresponding with the first frame ofaugmented reality image content; determining, using the processingcircuitry, second display augmented reality image data to be output tothe display panel to enable the display panel to display the secondframe of augmented reality image content at least in part by tonemapping the second augmented reality input image data in accordance withthe second local tone map grid.
 18. The method of claim 15, whereindetermining the first local tone map grid comprises: determining a firstperceived background brightness metric indicative of brightness level ofthe background image content expected to be perceived at a first pixelposition on the display panel during display of the first frame ofaugmented reality image content based at least in part on the firstfiltered background image data corresponding with the first pixelposition; determining a second perceived background brightness metricindicative of brightness level of the background image content expectedto be perceived at a second pixel position adjacent the first pixelposition on the display panel during display of the first frame ofaugmented reality image content based at least in part on the firstfiltered background image data corresponding with the second pixelposition; identifying the first pixel position and the second pixelposition as being included in a first grid zone of the first local tonemap grid when the first perceived background brightness metricassociated with the first pixel position matches the second perceivedbackground brightness metric associated with the second pixel position,wherein each pixel position included in the first grid zone isassociated with a first target tone mapping; and identifying the secondpixel position as being included in a second grid zone different fromthe first grid zone of the first local tone map grid when the secondperceived background brightness metric associated with the second pixelposition does not match the first perceived background brightness metricassociated with the first pixel position, wherein each pixel positionincluded in the second grid zone is associated with a second target tonemapping.
 19. Image processing circuitry configured to be deployed in anelectronic system to process augmented reality image data beforecorresponding augmented reality image content is displayed on a displaypanel of the electronic system, wherein the image processing circuitrycomprises: background re-projection circuitry configured to: receivecaptured background image data corresponding with a captured frame ofbackground image content over which the augmented reality image contentis expected to be displayed; determine re-projected background imagedata at least in part by processing the captured background image datato re-project the captured frame of background image content from animage sensor perspective to a viewing perspective provided by alight-transmissive viewing surface through which the background imagecontent is expected to be viewed; background filtering circuitrycommunicatively coupled to the background re-projection circuitry,wherein the background filtering circuitry is configured to determinefiltered background image data at least in part by low pass filteringthe re-projected background image data; background analysis circuitrycommunicatively coupled to the background filtering circuitry, whereinthe background analysis circuitry is configured to determine a perceivedbackground brightness metric indicative of background brightness levelexpected at a pixel position on the display panel during display of theaugmented reality image content based at least in part on the filteredbackground image data corresponding with the pixel position; and tonemapping circuitry communicatively coupled to the background filteringcircuitry, wherein the tone mapping circuitry is configured to processthe augmented reality image data at least in part by applying a tonemapping associated with the perceived background brightness metric tothe augmented reality image data corresponding with the pixel position.